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WIRING  OF  BUILDINGS  FOR  TELEPHONE  SERVICE 


HANDBOOK 


—  OF  — 


THE  PACIFIC  TELEPHONE  AND  TELEGRAPH  COMPANY 


FOR  THE 


GUIDANCE   OF  ARCHITECTS  AND  BUILDERS 


PREFACE 

The  problem  of  telephone  distribution  in  large  office  and  apartment  buildings 
has  grown  to  an  importance  that  demands  the  attention  of  architects  and  build- 
ers. Provision  should  be  made  in  all  such  modern  buildings  for  telephone  serv- 
ice and  the  same  consideration  should  be  given  it  as  for  gas,  water,  or  electric 
facilities.  In  order  to  conceal  unsightly  telephone  wires  and  cables,  and  avoid 
unnecessary  cutting  of  walls  and  floors,  provision  should  be  made  for  these  wires 
and  cables  during  the  construction  of  the  building.  The  Pacific  Telephone  and 
Telegraph  Company  issues  this  handbook  to  bring  about  a  uniformity  in  practice 
and  to  secure  the.  .economical  and,  proper  distribution  of  telephone  wires  and  ca- 
bles in  buildings,' :a-nd  wjll  gladly  assist  any  architect,  builder  or  owner  in  lay- 
ing out  the  telephony  .f-aqilities  for  a  -building  of  any  size  in  its  territory. 


THE   PACIFIC  TELEPHONE    AND    TELEGRAPH    CO. 
San  Francisco,  Cal.,  April  1,  1912. 


LIST  OF  PLATES 


Plate  I  General  Wiring  Arrangement 

Plate  II  Main  Terminal  Cabinet 

Plate  III  A  Telephone  Riser  Cable  Shaft 

Plate  IV  Floor  Location  of  Potheads 

Plate  V  Conduit  Used  for  Riser  Cables 

Plate  VI  Vent  Shaft  Used  for  Riser  Cables 

Plate  VII  Hall  Terminal  Cabinet 

Plate  VIII A.     Hall  &  Room  Moulding 

B.     Crossing  Conduit 

Plate  IX      Vertical  Distributing  System 

Plate  X       Floor  Conduit  Scheme  for  Permanent  Locations 

Plate  XI      Floor  Outlet 

Plate  XII     Typical  Office  Building  Floor  Plan 

Plate  XIII Typical  Apartment  Building  Floor  Plan 

28710 J 


LIST  OF  TABLES 


Table  I  Dimensions  for  Basement  Wall  Opening 

Table  II  Space  Occupied  by  a  Main  Terminal  Cabinet 

Table  III  Size  and  Weight  of  Riser  Cables 

Table  IV  Number  of  Riser  Shafts  Required 

Table  V  Riser  Shaft  Dimensions 

Table  VI  Space  for  Riser  Potheads 

Table  VII  Conduit  Sizes  for  Riser  Cables 

Table  VIII  Radii  of  Riser  Conduit  Bends 

Table  IX  Conduit  Sizes  for  Rubber  Covered  Wire 

Table  X  Conduit  Sizes  for  House  Cables 

Table  XI  Conduit  Sizes  for  Inter-Communicating  Systems 

Table  XII  Hall  Moulding  Dimensions 

Table  XIII  .  , Dimensions  for  Conduit  Boxes  at  Potheads 


SPECIFICATIONS  FOR  WIRING,  OF.  BUILDINGS 


1.  These  specifications  govern  the  choice  of  materials  knd  the  proper  methods 
to  be  employed  in  the  installation  of  telephone  facilities  in  all  new  and  remodeled 
buildings.  ' 

2.  Telephone  distribution  in  a  building  involves  the  running  of  three  or  more 
wires  from  each  telephone  to  a  central  point  near  the  entrance  of  the  telephone  wires 
or  cables.  When  a  number  of  telephone  wires  follow  a  general  direction  they  should 
be  grouped  in  cables.    When  the  telephone  wires  diverge  over  a  large  area,  the 
number  of  wires  in  a  group  is  so  reduced  that  a  distributing  cable  is  not  justified. 
In  this  case  the  riser  cable  is  terminated  in  a  cabinet  and  the  line  is  continued  to 
the    subscriber    station    by    means    of    three    approved    rubber    covered,    braided 
and  twisted  wires.     Plate  I  illustrates  a  general   wiring  arrangement    from    the 
"central  point"  in  the  basement. 

3.  The  basic  principle  involved  in  the  design  of  the  telephone  facilities  for  a 
building  is  simply  to  provide  shafts,  conduits,  and  mouldings  wherever  required 
and  arrange  them  in  such  a  manner  as  to  facilitate,  without  injuring  or  disfigur- 
ing the  interior,  the  installation  or  replacement  of  any  cable  or  wire  which  may  be 
required  to  furnish  service  to  any  part  of  the  building. 

4.  A  glossary  of  wiring  terms  used  is  appended. 


CLASSIFICATION  OF  BUILDINGS 

5.  Buildings  may  be  classine'd.  in  regard  to  the  distribution  of  telephone  facili- 
ties as  follows: 

(a)  Office  and  Loft  Buildings. 

(b)  Apartment  and  Hotel  Buildings. 

6.  This  classification  results  from  the  method  employed  in  designing  the  tele- 
phone facilities. 

7.  The  first  class  undergoes  a   shifting  of  telephonic  density,  which  precludes 
any  attempt  to  install  wires  permanently  in  any  given  location. 

8.  The  second  class  of  buildings  has  a  certain  telephonic  development,  which 
usually  may  be  considered  as  two  lines  per  apartment  and  one  line  per  hotel  room. 
Apartment  house  tenants  often  desire  a  direct  line  to  the  central  office  in  addition 
to  local  house  service. 

GENERAL  FACILITIES  FOR  ALL  TYPES  OF  BUILDINGS. 

9.     Provision  should  be  made   for  the   entrance   of  the   main   or   ex- 
change cable  into  the  basement.     This  entrance  will  be  made  in  all 
cases,  a  distance  of  approximately  two  (2)  feet,  below  ground  level.     This  cable 

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and  protecting  conduit  will  be  installed  by  the  Telephone  Company.     Information 
as  to  the  point  of  entrance  should  be  obtained  from  the  local  manager. 

10.  Table  I  gives  the  sizes  of  wall  openings  for  main  cable  entrance.  Hooks 
or  racks  should  be  installed  for  the  support  of  the  main  cable  from  its  point  of 
entry  to  the  main  terminal  cabinet.  These  supports  should  be  placed  at  inter- 
vals not  exceeding  three  (3)  feet. 

11.     Where  lead  covered  cables  are  connected  to  open  pairs  of  wires 
terminals  are  used.    Terminals  are  also  used  in  some  cases  for  con- 
nection between  two  lead  covered  cables.     They  consist  of  a  number  of  punch- 
ings  to  which  the  cable  wires  and  house  wires  are  connected,  either  by  soldering 
or  by  means  of  binding  posts. 

12.  These  terminals  are  located  in  cabinets  which  are  named  according  to 
their  location  or  their  function.  A  main  terminal  cabinet  is  installed  in  the  base- 
ment for  the  purpose  of  connecting  the  exchange  cables  to  the  riser  cables.  A 
hall  terminal  cabinet  is  installed  on  each  floor  in  the  vicinity  of  the  riser  shaft 
for  the  purpose  of  connecting  the  floor  cable  to  the  distributing  wires  from  the 
individual  telephones.  Distributing  cabinets  perform  the  same  function  as  hall 
terminal  cabinets,  except  that  they  are  located  at  points  distant  from  the  riser 
shaft.  The  cabinets  shown  on  the  plates  are  of  wood,  but  sheet  iron  cabinets  of 
the  same  form  may  be  used  in  fireproof  buildings. 

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MAIN  13.  Space  should  be  provided  near  the  foot  of  the  riser  cable  shaft 
TERMINAL  for  the  main  terminal  cabinet.  When  more  than  one  riser  shaft  is 
to  be  provided,  the  main  terminal  cabinet  should  be  located  at  the  central  point 
of  the  basement  end  of  the  group,  and  must  be  in  a  dry  place  and  accessible  at  all 
times.  An  electric  lighting  circuit  should  be  available  near  the  cabinet.  The  cab- 
inet and  connecting  strips  will  be  installed  by  the  Telephone  Company.  Plate  II 
shows  the  assembly  of  a  main  terminal  cabinet  and  Table  II  gives  the  minimum 
wall  space  required  for  a  given  number  of  lines. 

RISER        14.     All  cables  extending  from  the  main  terminal     to     the    various 
CABLES       floors  in  the  building  are  known  as  riser  cables.    When  riser  cables 
are  to  be  carried  any  distance  horizontally     through     the     basement,     supports 
should  be  provided  as  specified  for  the  main  cable.     Table  III  gives  the  dimen- 
sions and  weights  of  lead  covered  paper  insulated  cables  used  for  risers. 

RISER        15.     The  best  form  of  enclosure  for  riser  cables  is  a  vertical  shaft, 
SHAFTS       extending  through  every  floor  of  the  building.     These  shafts  may  be 
made  of  wood,  tile  or  steel,  but  should  be  of  uniform  cross  section  throughout 
their  length. 

16.     The  number  of  riser  shafts  required  in  a  building  depends  upon  the  height, 
floor  area  and  the  number  of  telephones.     Table  IV,  A  to  E,  gives  the  approxi- 

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mate  number  of  shafts  for  rectangular  buildings  of  known  ground  area  and  tele- 
phonic density.  For  example :  A  10  story  office  building  having  an  area  of  30,000 
sq.  ft.  per  floor  would  require  4  riser  shafts  if  the  expected  density  is  one  tele- 
phone per  250  sq.  ft.  of  floor  space.  (See  Table  IV-A).  In  general,  all  shafts 
should  be  in  the  center  of  equal  areas.  The  number  of  shafts  should  never  be  so 
great  as  to  reduce  the  number  of  wires  in  the  floor  cables  to  less  than  10  pairs. 

17.  It  is  inadvisable  to  erect  risers  in  elevator  shafts.  When  riser  shafts 
cannot  be  erected  separately,  provision  should  be  made  for  carrying  the  cables  in 
vent  shafts  or  conduits.  The  cable  need  not  be  incased  except  at  points  where 
it  may  be  subject  to  abrasion  or  present  a  bad  appearance.  When  riser  cables 
are  to  be  erected  in  vent  shafts,  provision  must  be  made  for  supporting  them 
and  for  the  entry  of  the  floor  cables  at  each  floor.  No  pipes,  cables  or  wires 
will  be  permitted  in  the  riser  shaft  other  than  those  installed  by  the  Tele- 
phone Company.  Plate  VI  shows  an  approved  method  of  erecting  riser  cables 
in  vent  shafts.  Table  V  gives  the  minimum  dimensions  of  riser  shafts  for  a 
given  number  of  lines. 

RISER  CABLE     18.     All  riser  cables  should  be  supported  at  each  floor  by  approved 
SUPPORTS       clamps  secured  to  nailing  strips  in  the  shaft. 

19.  All  nailing  strips  should  be  2"x4"  in  cross  section  in  each  shaft,  as 
shown  on  Plate  III.  Access  should  be  had  to  the  headers  by  shaft  openings, 


which  may  be  covered  by  the  floor  terminal  doors,  or  by  separate  covers  screwed 
to  the  shaft  walls. 

LOCATION  20.  Plate  IV  shows  the  floor  location  of  all  splicing  points  in  a  build- 
OF  ing,  whether  fed  by  one  or  more  risers.  At  each  splicing  point  pro- 

POTHEADS  vision  should  be  made  in  the  shaft  for  a  pothead.  Table  VI  gives  the 
dimensions  of  the  shaft  at  such  points.  Plate  III  illustrates  a  method  of  covering 
the  splicing  cabinet  with  a  removable  panel. 

RISER         21.     When  it  is  impossible  to  install  riser  shafts  or  to  utilize  vents, 
CONDUIT      conduit  may  be  used  for  riser  cables. 

22.  Not  larger  than  200  pair  cables  should   be   installed   in   conduit.     A   spare 
conduit,  1"  in  diameter,  should  be  installed  between  all  floors  to  allow  for  inter- 
connection. 

23.  All  splices  will  be  located  at  floors  indicated  on  Plate  IV  and  all  conduit 
should  terminate  in  splicing  cabinets  at  these  points. 

24.  Plate  V  shows  an  approved  method  of  installing  riser  conduit,  and  the  lo- 
cation of  splices  and  terminals. 

25.  All  floor  cables  will  be  carried  in  individual  conduits  from  the  splicing  cabi- 
net to  their  respective  floor  terminals. 


26.  All  riser  conduits  should  be  fairly  free  from  bends.     Table  VII  gives  the 
sizes  of  riser  conduits.     When  a  bend  is  necessary  the  radius  of  curvature  will 
be  governed  by  Table  VIII. 

27.  All  riser  conduits  should  be  carefully    inspected     for     rough  projections 
which  might  injure  the  cable.    They  should  be  tagged,  fished  and  plugged  to  keep 
out  dirt  when  not  used. 

28.  Conduits  may  be  placed  near  other  service  wires,  pipes,  etc.,  with  the  ex- 
ception of  steam  and  hot  water  mains.  \ 

29.  All  riser  conduits  should  terminate  in  the  basement  without  a  bendt     and 
provision  should  be  made  for  the  main  terminal   cabinet  on   the  left  side  of  the 
conduit  opening. 

30.  Table  VI  governs  the  size  of  the  splicing  cabinets. 

31.  A  2"x4"  nailing  strip  should  be  placed  in  the  rear  wall  of  each  splicing  cab- 
inet at  a  point  near  the  center  as  specified  under  "Riser  Cable  Supports." 

HALL  32.  In  all  types  of  buildings  using  shafts  or  conduits  for  riser  cables, 
TERMINAL  terminal  cabinets  should  be  installed  below  the  corridor  mouldings 
CABINETS  an(j  jn  dose  proximity  to  the  riser  shaft. 

33.     Plates  III,  V,  and  VI  illustrate  approved    methods  of  mounting     terminal 
cabinets. 

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34.  When  mounted  in  the  front  wall  of  the  shaft,  they  should  not  obstruct  the 
passage  of  cables.    They  should  have  a  hinged  door  provided  with  a  spring  catch. 
Plate  VII   shows  two  types  of  approved  terminal  cabinets,  and  gives  tables  of 
minimum  dimensions.     All  cabinets  should  be  bored  for  the  entrance  of  cables 
and  distributing  wires.  » 

35.  Proper  sizes  of  conduit,  as  specified  in  Table  IX,  should  be  installed  be- 
tween the  hall  mouldings,  and  between  the  hall  moulding  and  the  distributing  cab- 
inet. 

36.  The  terminals  will  be  mounted  in  the  cabinets  by  the  Telephone  Com- 
pany. 

FLOOR  DISTRIBUTION  FOR  HOTELS. 

37.  When  the  number  and  location  of  the  telephones  are  known,  the  building 
may  be  wired  in  a  permanent  manner. 

38.  Conduits  of  the  proper  size  may  be  installed  from  the  hall  terminal  cabinet 
to  each  room.     These  conduits  may  carry  a  number  of  wires  and  feed  a  portion 
of  the  floor.     At  distributing  points  outlet   boxes   should    be    provided.     These 
boxes  should  be  placed  adjacent  to  the  hall  or  room  moulding  and  be  easily  ac- 
cessible. 

39.  When  the  exact  location  of  the  telephone  is  known,  a  conduit  may  be  in- 

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stalled  from  the  upper  edge  of  the  moulding,  or  from  the  outlet  box  to  the  point 
of  attachment  of  the  instrument.  Where  wall  type  instruments  are  to  be  used, 
the  conduits  should  open  outward  at  a  point  4'  10"  above  the  finished  floor. 
Where  portable  types  are  used,  the  conduits  should  open  outward  at  the  upper 
edge  of  the  mop  board.  The  openings  should  be  flush  with  the  finished  wall. 

DISTRIBUTING  40-  When  a  single  riser  shaft  is  used  for  feeding  more  than  thirty 
TERMINAL  (30)  telephones  per  floor  it  may  be  advisable  to  make  several  taps 
CABINETS  anc|  locate  distributing  cabinets  at  the  centers  of  distribution.  The 

specifications  for  hall  terminal  cabinets  also  apply  to  distributing  cabinets.     They 

should  be  installed  flush  with  the  wall  just  below  the  moulding  and  be  connected 

thereto  by  two  conduits  of  proper  size. 

41.  These  cabinets  may  be  located  accurately  by  marking  each  station  upon 
the  floor  plan,  and  grouping  those  whose  wires  will  traverse  a  distance  exceeding 
fifty   (50')   feet  in  the  same  direction.     Usually  sub-cabinets   will  be  located   at 
points  where  corridors  meet  or  intersect.     Plate  VII  shows  a  distributing  cabi- 
net in  position. 

42.  Floor  cables  may  be  installed  in  conduits  or  laid  along  corridor  mouldings. 
Table  X  gives  the  dimensions  of  conduits  for  different  sizes  of  lead  covered  floor 
cables. 

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WIRING  OF  APARTMENT  BUILDINGS. 

43.  When  the  number  of  apartments  per  floor  exceeds  three,  a  terminal  should 
be  located  on  each  floor  and  a  riser  shaft  or  conduit  provided  as  specified. 

44.  On  account  of  the  shifting  of  telephones   no   floor   wiring  should  be  of  a 
permanent  character.     Seldom  will  the  development  justify  more  than  one  riser, 
and  unless  the  shape  of  the  building  demands,  all  wires  on  a  floor  will  distribute 
from  one  terminal.     Where  on  account  of  the  absence  of  hall  mouldings,  a  central 
shaft  cannot  be  provided,  the  facilities  should  consist  of  vertical  conduit  as  shown* 
on  Plate  IX,  distributed  on  each  floor  as  shown  on  Plate  XIII. 

45.  Each  apartment  should  be  connected  by  moulding  or  conduit  to  the  floor 
terminal.     No  attempt  should  be  made  to  install  conduit  between  the  moulding 
and  the  point  of  attachment  of  the  instrument.      All   room    moulding   should   be 
connected  by  y^"  conduit,  where  walls  or  other  obstructions  intervene.     This  will 
permit  the  passage  of  wires  without  boring  holes  through  finished  walls. 

MOULDINGS       ^-     The  best  method  for  supporting  and  concealing     wires,  which 
extend  from  the  floor  cabinet  to  the  instrument,  is  to  use  the  corri- 
dor and  room  moulding.    The  area  of  the  moulding  trough  should  be  sufficient  to- 
carry  all  necessary  wires  and  cable. 

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47.  Plate  VIII  shows  a  section  of  room  and  hall  moulding  with  partition  con- 
duits, and  Table  XII  gives  the  trough  dimensions  for  concealing  wires  and  cables. 
All  room  moulding  should  have  minimum  trough  dimensions  of 


48.  Where  a  wall  intercepts  a  line  of  moulding,  or  where  for  any  reason, 
cable  or  wires  must  pass  an  obstruction,  a  conduit  path  of  proper  size,  as  speci- 
fied in  Tables  IX  and  X,  should  be  provided. 

CONNECTING  49.  In  buildings  provided  with  hall  mouldings  every  apartment 
HAROOMNE  should  be  connected  by  a  ^2"  conduit  to  these  mouldings.  This  con- 
MOULDING  duit  should  be  located  at  the  corner  of  the  room  nearest  the  floor  ter- 

minal cabinet  so  as  to  reduce  to  a  minimum   the  length  of  wire  required.     Plate 

VIII  shows  the  proper  use  of  such  a  conduit. 

CROSSING  50.  A  crossing  conduit  should  be  installed  at  every  floor  cabinet  and 
CORRIDORS  at  intersections  of  halls,  to  avoid  exposed  wiring  and  long  runs  of 
AND  HALLS  wire  around  the  ends  of  hallways. 

51.  Plate  VIII  shows  such  a  conduit  between   two   hall    mouldings   and   illus- 
trates the  method  of  opening  the  conduits  into  outlet  boxes. 

52.  Where  a  crossing  conduit  connects  with  a  terminal  cabinet,  it  should  enter 
at  the  upper  right  hand  corner,  adjacent  to  the  conduit  which  leads  to  the  mould- 
ing, as  shown  on  Plate  III. 

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APARTMENT      53.     When  a  flush  type  vestibule  set  is  to  be  used  for  connection  to 
VESTIBULE       a  local  apartment  house  system,  provision  should  be  made  for  lead 
SETS  cove'red  cable  of  the  proper  size  to  be  run  in  conduit  or  shafting  to 

the  foot  of  the  riser  shaft. 

54.  The  vestibule  set  will  be  mounted  in  a  wooden  box  which  is  set  into  and 
flush  with  the  finished  wall.  The  dimensions  of  this  box  vary  with  the  capacity 
and  may  be  obtained  by  consultation  with  the  local  manager. 


OFFICE  AND  LOFT  BUILDINGS. 

TELEPHONE  55.  Considerable  study  is  required  in  determining  the  maximum 
DEoIFFioEIN  number  of  telephones  that  will  be  required  in  an  office  building  and 
BUILDINGS  the  distribution  on  the  various  floors. 

56.  The  total  number  of  telephones  in  a  building  will  not  vary  greatly     and 
may  be  determined  in  the  following  manner: 

57.  Determine  by  inquiry  the  number  of  telephones  in  adjacent  buildings  used 
for  similar  purposes  and  housing  the  same   class   of   tenants.      Divide   the    total 
floor  area  of  these  buildings  by  the  total   number   of  telephones   and   obtain   for 
the  locality  the  number  of  square  feet  per   telephone.     This     constant    may    be 
divided  into  the  total  floor  area  of  the   building  in   question  to   determine   the 
average  total  number  of  telephones. 

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58.  The  maximum  number  of  telephones  in  the  building  at  one  time  is  esti- 
mated from  the  following: 

(a)  The  character  and  business  prospects  of  the  vicinity. 

(b)  The  present  condition  of  business. 

(c)  •    The  average  number  of  telephones  determined  by  comparison. 

59.  The  maximum  number  of  telephones  mentioned  above  should  be  divided  by 
the  number  of  floors  to  obtain  the  average  maximum  number  of  telephones  per 
floor.     This  value  is  used  in  all  calculations  and  is  the  one  referred  to  in  con- 
nection with  the  floor  cabinets.    This  average  may  be  modified  for  each  floor  by 
a  consideration  of  the  following  items: 

(a)  The  relative  size  of  the  offices  on  different  floors. 

(b)  The  relative  rental  value  of  the  different  floors. 

(c)  Special  long  leases  of  tenants,  whose  demands  for  service  are  known. 

60.  The  locations  of  the  telephones  in  the  rooms  are  not  permanent,  and  may 
be  changed  to  meet  the  requirements  of  the  tenants. 

WIRING       61-     All  shafts  or  conduits  should  be  run  as  specified  from  the  point 
of  entrance  in  the  basement  to  the  floor  cabinets. 

62.  All  wiring  should  be  of  temporary  character  from  the  floor  cabinets  to  the 
various  parts  of  the  building.  No  conduits  should  be  installed  for  floor  wires. 
Plate  XII  shows  a  typical  office  building  floor  plan. 

13 


63.     Where  several  risers  are  used  no  sub-cabinets  need  be  installed. 
CABINETS     64'     All  cabinets  and  sub-cabinets  shall  be  of  double  the  capacity, 
that  would  be  demanded  by  average  development. 

RISER  SHAFTS  65.     All  riser  shafts  and  conduits  should  have  a  capacity  30%  great- 
AND  er   than   that   determined   by  the  estimated  development,  to  allow  for 

CONDUIT       flexibility. 

DISTRIBUTING  66.     Where  on  account  of  the  design  of  the  building  only  one  riser 
CABINETS       shaft  can  be  provided,  but  the  number  of  telephones  justifies  more, 
distributing   cabinets   should   be   installed  at  the  various  centers  of  distribution. 
These  cabinets  should  be  connected  by  lead  covered  cables  to  the  riser  cable. 

67.  These  connecting  cables  should  have  twice  the  number  of  wires  required 
for  average  development.  Provision  should  be  made  for  carrying  such  cables  on 
mouldings  or  in  conduits  as  desired. 

CROSSING      68.     Crossing  conduits  should  be  installed  where  needed,  as  specified 
CONDUITS     for  hotels  and  apartments. 

69.     All  offices  should  be  connected  to  the  hall  moulding  by  24"  conduit. 

MOULDINGS    ^'     ^-a^   anc^   room    mouldings  should  be  provided  for  distributing- 
wires.    They  should  be  of  such  dimensions   as   to   carry  double  the 
number  required  by  the  expected  development.     Plate  VIII  shows  an  approved 
type  of  moulding.     Table  XII  gives  dimensions  of  moulding  troughs  for  various 
sizes  of  cables. 

14 


PERMANENT  LOCATIONS  IN  LARGE   OFFICES. 

71.  When  specified  by  the  owners,  offices  may  be  wired  permanently  from  the 
floor  outlets.  In  such  cases  care  must  be  taken  to  accurately  locate  the  conduit 
•outlets,  so  that  they  will  be  adjacent  to  the  probable  location  of  desks  and  tables. 

72.  All  conduits  should  be  of  the  proper   size   as   specified   in   Table   IX   and 
should  have  a  minimum  number  of  bends  between  outlets.    Plate  X  shows  such 
a  conduit  arrangement.     All  conduit  should  be  fished,  tagged  and  plugged  during 
installation.    Conduit  smaller  than  £4"  should  not  be  used  in  long  runs. 

73.  Where  it  is  expected  that  inter-communicating  service  will  be  required 
the  sizes  of  conduit  should  be  determined  from  Table  X,  which  shows  the  size  of 
conduit  required  for  a  given  total  number  of  telephones  in  the  office.    These  sizes 
are  based  upon  the  use  of  cable  and  should  obtain  in  all  parts  of  the  system.    The 
diameter  of  the  outlet  shown  on  Plate  XI  should  be  not  less  than  \y2"  to  admit 
two  cables,  one  from  either  direction. 

FLOOR        74.     The    conduit   should   terminate  in  a  water  tight  outlet  set  flush 
CONDUIT      with  the  finished  floor,  at  a  point  in  the  floor  adjacent  to  the  pro- 
OPENING      posed  location  of  the  telephone.     It  should  be  capped  flush  to  keep 
•out  dirt  while  not  in  use. 

OUTLET       ^'     l^e  *yPe  °*  fl°or  out^et  box  shown  on  Plate  XI  is  approved  by 
BOXES        the  Telephone  Company,  and  on  account  of  its  low  price  is  preferable 
to  any  other  type  of  electric  floor  outlet  now  on  the  market. 

15 


76.     All  connections  to  telephones  and  to  portions  of  cables  will  be 

w v  -  •          i  •         1  1         /T\     11  /•— »  /T\I    •  • 

STRIPS  made  on  a  terminal  strip  by  the  lelephone  Company.  1  his  terminal 
strip  will  be  mounted  on  the  side  of  a  desk  in  an  inconspicuous  place  at  a  point 
not  less  than  one  (!')  foot  above  the  finished  floor. 

PRIVATE   EXCHANGES. 

77.  When  a  switchboard  is  to  be  located  in  a  certain  office,  no  facilities  are 
needed  other  than  those  which  are  to  be  provided   for  the   expected   telephonic 
development. 

78.  When  a  large  majority  of  the  telephones  in  a  building  are  connected  to  one 
switchboard,  special  provision  of  space  may  be  necessary.    In  such  cases  the  dimen- 
sions of  the  board  and  the  size  of  the  battery  room  should  be  determined  by  con- 
sultation with  the  local  telephone  manager. 

79.  The  capacity  of  the  switchboard  will  be  determined  by  the  local  manager. 

80.  The  facilities  for  cable  to  the  switchboard  should  suffice  for  the  ultimate 
capacity  of  the  board  in  lines  and  trunks,as  all  wires  from  the  switchboard  must  go 
to  the  main  terminal  cabinet  in  the  basement. 

81.  The  battery  room  is  usually  located  in  the  basement. 

16 


WIRING   SPECIFICATIONS. 

82.  When  a  contract  calls  for  the  complete  wiring  of  all  floors,  as  well  as 
the  provision  of  riser  shaft  and  terminal  cabinets,  the  following  specifications  will 
govern  the  choice  of  material  and  methods  of  installation. 

FLOOR  83.  All  cables  used  for  interior  construction  shall  be  lead  covered 
CABLES  anci  waterproof.  The  core  shall  be  made  up  of  No.  22  B.  &  S.  gauge 
conductors  arranged  in  twisted  pairs.  Each  conductor  shall  have  a  double  silk  and 
single  cotton  insulation  so  colored,  as  to  distinguish  it  and  its  mate  from  all  of  the 
other  wires  in  the  cable.  It  shall  have  an  insulation  resistance  of  100  megohms 
per  mile. 

84.  The  floor  cables  should  be  installed  in  an  approved  manner  between  the 
riser  pothead  and  the  hall  terminal  cabinets.  The  cables  should  not  be  formed  and 
connected  to  the  terminals  by  the  builder,  as  the  Telephone  Company  prefers  to 
complete  this  work  at  the  time  of  installation  of  the  telephones. 

HOUSE  85.  All  wiring  between  terminal  cabinets  and  the  telephone  instru- 
WIRING  ments  should  be  done  with  wire  not  smaller  than  No.  19  B.  &  S. 
gauge.  This  wire  should  have  a  good  rubber  insulation,  and  be  not  less  than 
3/32"  in  diameter,  measured  over  the  rubber  insulation  of  any  conductor. 
The  rubber  should  be  protected  by  a  close  braid  over  each  conductor.  The  two 
conductors  of  a  pair  should  be  twisted  together  with  one  complete  twist  in  every 

three  inches. 

17 


86.  All  wiring  shall  be  so  placed  as  to  be  easily  removable.    No  wiring  should 
be  sealed  in  the  plaster  on  account  of  the  rapid  deterioration  of  the  wires  and 
the  impracticability  of  replacing  them  in  the  same  manner. 

87.  All    soldered    connections   between  wires  should  be  taped  with  rubber  tape, 
and  then  covered  with  approved  friction  tape.    All  joints  in  a  twisted  pair  should 
be  separated  at  least  six   (6)   inches. 

88.  At  points  of  connection  to  the  terminal  and  telephones,  all  wires  should 
have   a   spare   length   of   forty-eight    (48)  inches. 

89.  If   wires   require  stapling,   no   two  wires  should  be  secured  under  one  sta- 
ple, and  only  staples  having  insulated  heads  should  be  used. 

90.  The  number  of  wires  required  for  each  telephone  will  depend  on  the  system 
to  be  installed,  and  this  information  should  be  obtained  from  the  Telephone  Com- 
pany. 


18 


CABINET 


CONDUIT 


DENSITY 


GLOSSARY. 

A  box   with   finished   hinged   cover   containing   terminals   to   which 
are  connected  the  cable  conductors  and  house  wires. 

A  hollow  cylindrical  pipe  made  of  wrought  iron  or  clay,  used  to  en- 
case the  wires  and  cables. 

The  number  of  square  feet  of  floor  space  per  telephone. 
Referring  to  the  extent  of  the  demand  for  telephone  service. 

FACILITIES     Refers    to   the    routes    which  are  provided  for  telephone  wires  while 
the   building  is   under  construction. 

FISH         To  run  a  wire  through  a  conduit  or  space  between  walls. 

A  small  leg  of  cable,  which  serves  the  telephones  on  a  floor,  and  splices 
to  the  main  cable  at  a  pothead. 

A  large  cylinder  of  lead  enclosing  a  splice  between  the  riser  cables 
and  several  floor  cables.        ( 

A  main  cable  extending  from  the  basement  terminal  to  all  floors  re- 
quiring telephone  service. 


FLOOR  CABLE 


POTHEAD 


RISER 


Table  I 


Dimensions  for  Basement  Wall  Opening. 

Number   of  Lines   in  Building 400  800 

Dimensions    of   Opening 5"x5"  5"xlO" 


1200 
5"xl5' 


Table  II 


Wall  Space  Occupied  by   a 
Capacity  of  Cabinet. 

No.  of  Prs.  No.  of  Prs. 

of  Wires  of  Wires 

To  Exchange  To  Building 

100  100 

200  200 

300  300 

600  600 

800  800 


Main   Terminal  Cabinet. 

See  Plate  II. 

Dimensions  Dimensions 

"A"  "B" 

5'0"  2'6" 

4'6"  2'6" 

4'6"  2'6" 

4'6"  5'6" 

4'6"  8'0" 


No.  of  Pairs..      10 
Outside    Dia..  17/32" 
Lbs.  Wt.  pr.  Ft.  .647 


Table  III 

Size  and  Weight  of  Riser  Cables. 


25 

23/32" 
,963 


50 

15/16" 
1.35 


75     100 

1  3/32"  1  5/16" 

.1.75    2.25 


150 

1  17/32" 
2.81 


200 


4,1 


250 

1  15/16" 
4,7 


300 

2  1/16" 
5.14 


400 


6.3 


Table  IV 

Total  Number  of  Riser  Shafts  Required. 

Density=l  telephone  per  250  sq.  ft.  of  floor  space. 

Floors   2                 4                 6                 8                10  12  14               16               18 

Sq.  Ft.  per 

Floor  Number  of  Eiser  Shafts  Eequired 

2000     1                 1                 1                 1                 1  1  1                1                1 

5000     2                 1                 1                 1                 1  1  1                 1                1 

A.  10000 4                 2                 1                 1                 1  1  1                 1                 1 

20000  4                 4                 2                 2                 2  2  1                 1                 1 

30000   6                 4                 4                 4                 4  2  2                 2                 2 

50000  10                 8                 8                8                 8  6  6                4                4 

Density=l  telephone  per  500  sq.  ft.  of  floor  space. 

Floors   2                4                6                8               10  12  14              16               18 

Sq.  Ft.  per 

Floor  Number  of  Eiser  Shafts  Eequired 

2000  1       1       1       1       1  1  1       1       1 

5000  2       1       1       1       1  1  1       1       1 

10000  2       1       1       I       1  1  1       1       1 

B.  20000  4       2       1       1       1  1  1       1       1 

30000  6       6       4       4       4  4  4       2       2 

45000  8       8       6       6      .6  6  4       4       4 

60000  10       8       8       8       6  6  6       4       4 

21 


c. 


D. 


E. 


Density=l 
Floors 

telephone 

2 

per  1000 
4 

1 
1 
1 

2 
4 
6 
per  2000 

4 

1 
1 
1 
2 
4 
6 
per  3000 
4 

1 
1 
1 
2 
4 

sq.  ft. 
6 

1 
1 
1 
2 
4 
6 
sq.  ft. 
6 

1 
1 
1 
2 
4 
6 
sq.  ft. 
6 

1 
1 
1 
2 
4 

of  floor  space. 
8                10 

Number  of  Eiser 
1                 1 
1                 1 
1                 1 
1                 1 
4                 4 
6                 4 
of  floor  space. 
8                10 

Number  of  Riser 
1                 1 
1                  1 
1                  1 
2                 2 
4                 4 
4                 4 
of  floor  space. 
8                10 

Number  of  Eiser 
1                 1 
1                 1 
1                 1 
1                 1 
4                 2 

22 

12 

Shafts 
1 
1 
1 
1 
4 
4 

12 

Shafts 
1 
1 
1 
1 
4 
4 

12 

Shafts 
1 
1 
1 
1 
2 

14 

Required 
1 
1 
1 
1 
2 
4 

14 

Eequired 
1 
1 
1 
1 
4 
4 

14 

Bequired 
1 
1 
1 
1 
2 

16 

1 
1 
1 
1 

2 
4 

16 

1 
1 
1 
1 
4 
4 

16 

1 
1 
1 
1 

2 

15 

1 
1 
1 
1 
2 
4 

18 

1 
1 
1 
1 
2 
4 

18 

1 
1 
1 
1 
2 

Sq.  Ft.  per 
Floor 
2000     . 

1 

5000     . 

1 

10000    . 

1 

24000  . 

4 

48000  . 

6 

60000  . 

8 

Density=l 
Floors 

telephone 

2 

Sq.  Ft.  per 
Floor 
2000     . 

1 

5000     . 

1 

10000  . 

1 

40000  . 

4 

80000   . 

6 

120000  . 

8 

Density=l 
Floors 

telephone 
2 

Sq.  Ft.  per 
Floor 
2000     . 

1 

5000     . 

1 

10000   . 

1 

60000   . 

4 

120000  . 

6 

Table  V 

Riser  Shaft  Dimensions. 

Prs.  of  Wires  in  Shaft 100  200  400  800 

Shaft  Dimensions    4"x6"  4"x6"  6"xlO"  6"xl2" 

Table  VI 

Space  for  Riser  Potheads. 

Prs.  of  Wires  in  Shaft 100  200  400  800 

Dim.   of   Splicing   Cabinet 4"x6"x33"         4"x8"x36"  6"xlO"x48"  6"xl2"x60" 

Table  VII 

Conduit  Sizes  for  Riser  Cables. 

No.  of  Prs.  in  Cable 15  25  50  100  200 

Size  of  Conduit 1^4"  1^4"  1%"  2"  2%" 

Table  VIII 

Radii  of  Curvature  in  Riser  Conduit  Bends. 

Size    of   Conduit 1%"  1%"  2"  2%"  3" 

Eadii    12"  18"  24"  30"  36" 

23 


Table  IX 

Conduit  Sizes  for  Rubber  Covered  Wire. 
Prs.  of  Wires 2  5  10  20  40 

Size   of   Conduit 1/2"  %"  1"  3  !4"  2" 

Table  X 

Conduit  Sizes  for  House   Cables. 

Pairs  in  Cable 5  10  20  30 

Conduit   Sizes    %"  Vs"  1"  1%' 

Table  XI 

Conduit  Sizes, 

For  Intercommunicating  Systems. 

Number  of  Min.  Dia.  of 

Telephones  Conduit 

10  1" 

20  iy2" 

30  1%" 

24 


Table  XII 

Moulding  Dimensions. 

Sizes 

Trough  Depth                                of  Open 

&  Width                                  Cable  Wires 

%                                        5  Pr.  5  Pr. 

%                                       15  Pr.  7  Pr. 

%                                       25  Pr.  N      10  Pr. 

1                                         50  Pr.  15  Pr. 

Table  XIII 

Dimensions  of  Conduit  Boxes  at  Potheads. 

Pairs 

in  Space  Occupied 

Cable  By  Potheads 

100  3"xl2"x36" 

200  4"xl4"x36" 

400  4"xl8"x60" 

800  4"xl8"x60" 


tfe 


n>  n>  n  n  n 


r 


.1 


z° 

n? 


27 


-   - 


-i    " 

0.    D 

it 

ri 

£ 
CO 
+J 

c 
0 


Table  of  Dimensions  for  Fig.  1 

Maximum  Capacity 
of  Box  in 
Pairs  of  Wires 

Length  of  Box 
Dimensions  "A" 

<i              __.  7 

7  PAIRS 

9%" 

11 

12%" 

16 

16V 

21 

20',s" 

26 

22" 

\ 

1 
/ 

== 
0 

7 

i 

! 

1 

\- 

Minimum  Inside  Dimensions  for 
Narrow  Boxes.     Fig.  1. 

-  — 

Table  of  Dimensions  for  Fig.  2 

Maximum  Capacity 
of  Box  in 
Pairs  of  Wires 

Length  of  Box 
Dimensions  "A" 

14  PAIRS 

9%" 

22 

12%" 

32 

18%" 

Minimum  Inside  Dimensions  for 
\Vide  Boxes.     Fig.  2. 


NOTE' 


MDICATC3  CONDUIT  IN  FLOOR  . 

WITH  SIZE-  ^»,' 

-----  M  -----    INDICATE*  TCUEPHONE  OUTLETS     ,' 

AS  PER  PILATE  XI- 
A  --------  MAIN   RISER  TERMINAL- 

B  --------  SUB-  OJSTWBUTING  TERMINAL"  ,' 


_.-•*  'i 

/*, 

•v' 

/         . 

"1 

\V  acfPBtf                          > 
I                             HALL                      X_ 
\ 

r 

ri 

•^ 

:  JCVATOI 

•T 
i  J 

1  '  i 

y^/^^2v|A^J 


fT     T     T     T     ? 
akiiJkkk 


35 


x  i 


I    I    I    I 
i_i_  i  a 


55  -  1  ,i-     1  -  93    .  . 


T3*  "T35F         F*      SBf  "™'~"T"""mTl5r*'"JT 


38 


ILLUMINATION 


LIST  OF  TABLES. 


TABLE     1.     Required  Intensity  of  Illumination. 

TABLE    2.     Intensity  of  Illumination  in  Foot  Candles  on  Horizontal  Planes. 

TABLE    3.     Illumination  from  Mazda  Lamps  (small  size)  with  Extensive  Holo- 
phane  Reflectors. 

TABLE    4.     Illumination  from  Mazda  Lamps  (large  size)  with  Extensive  Holo- 
phane  Reflectors. 

TABLE     5.     Illumination  from  Mazda  Lamps  (small  sizes)  with  Intensive  Holo- 
phane  Reflectors. 

TABLE    6.     Illumination  from  Mazda  Lamps  (large  sizes)  with  Intensive  Holo- 
phane  Reflectors. 

TABLE     7.     Illumination  from  Mazda  Lamps  (small  sizes)  with  Focusing  Holo- 
phane  Reflectors. 

TABLE    8.     Illumination  from  Mazda  Lamps  (large  sizes)  with  Focusing  Holo- 
phane  Reflectors. 


TABLE    9.  Reflection  Co-efficients  of  Walls  and  Ceilings. 

TABLE  10.  Average  Percentage  of  Reflection  from  Walls  and  Ceilings. 

TABLE  11.  Spacing  of  Units  for  Uniform  Illumination. 

TABLE  12.  Current  Taken  by  Incandescent  Lamps. 

TABLE  13.  Carrying  Capacity  of  Wire  (N.  E.  C.). 

TABLE  14.  Size  of  Wire  for  One  Volt  Drop. 

TABLE  15.  Total  Cost  of  Lighting  with  Mazda  Lamps. 

TABLE  16.  Total  Cost  of  Lighting  with  Tantalum  Lamps. 

TABLE  17.  Total  Cost  of  Lighting  with  Gem  Lamps. 

TABLE  18.  Total  Cost  of  Lighting  with  Carbon  Lamps. 

TABLE  19.  Intrinsic  Brilliancy  of  Light  Sources. 

TABLE  20.  Lumens  for  Various  Incandescent  Lamps. 


2 


ILLUMINATION 

Since  the  wiring  of  buildings  for  electric  lighting  is  so  closely  related  to  the 
wiring  of  buildings  for  telephone  service,  we  have  secured  permission  from  the 
National  Electric  Lamp  Association  to  publish  in  this  appendix  the  following  data 
which  has  been  slightly  rearranged  for  convenience. 

Only  a  small  portion  of  this  appendix  is  devoted  to  the  subject  of  "Wiring,"  as 
this  subject  has  been  treated  extensively  by  the  National  Board  of  Fire  Under- 
writers and  is  generally  understood  by  all  architects  and  builders. 

Illumination  is  not  so  generally  understood  on  account  of  its  recent  development 
along  scientific  lines.  The  major  portion  of  this  appendix  is  devoted,  therefore, 
to  outlining  the  method  of  laying  out  a  lighting  system  in  a  building  and  to  sup- 
plying working  data,  so  as  to  simplify  the  calculations  required  in  the  study. 

REQUIREMENTS  FOR  GOOD  ILLUMINATION. 

Illumination  must  be  acceptable  to  the  eye.  We  should  be  able  to  see  objects 
clearly  and  with  a  minimum  of  fatigue.  To  accomplish  this  result,  certain  condi- 
tions must  be  fulfilled. 

(a)  There  must  be  sufficient  illumination.  Since  objects  are  seen  by  means 
of  the  amount  of  light  which  they  reflect,  more  light  must  be  thrown  on  dark  ob- 
jects than  on  light  ones. 

3 


(b)  There  must  not  be  too  much  illumination.     Too  strong  a  light  tires  the 
eye. 

(c)  Intensely  bright  lights  in  the  field  of  vision  should  be  avoided.     The  in- 
trinsic brilliancy  or  candle  power  per  square  inch  of  luminous  area  should  there- 
fore be  kept  as  low  as  possible,  not  ordinarily  greater  than  4  to  6,  if  the  source  of 
light  is  in  the  field  of  vision.     Incandescent  lamps  should  either  be  shaded  or 
frosted.     See  Table  No.  19. 

(d)  Flickering  lights  should  be  avoided. 

(e)  Lamps  should  be  shaded  or  so  placed  that  the  direct  rays  do  not  strike  the 
eye. 

(f)  Streaks  or  striations  are  very  undesirable. 

(g)  A  satisfactorv  light  must  be  of  a  proper  quality.     It  should  have  a  contin- 
uous spectrum,  i.  e.%  one  containing  every  color  in  order  that  the  relative  color 
values  of  objects  illuminated  may  be  the  same  as  when  seen  by  daylight.    Avoid 
cold,  glaring  lights  which  are  too  rich  in  green  and  blue. 

DESIGNING  THE  ILLUMINATION  FOR  A  BUILDING. 

POINT  BY     1-     Divide  each  floor  or  each  room  into  areas  in  which  a  different  in- 

POINT        tensity  of  illumination  is  desired.     Consult  Table  1  or  other  author- 

METHOD      ities  upon  the  foot  candles  required  in  the  various  areas.  A  foot  candle 

of  illumination  is  the  amount  of  light  which  illuminates  a  point  one  foot  distant 

from  a  source  of  light  having  an  intensity  of  one  candle  power. 

4 


2.  Divide  each  of  the  areas  into  a  number  of  equal  squares  in  the  center    of 
which  luminants  are  to  be  installed.    The  number   of  such  sub-divisions  depends 
upon  the  degree  of  uniformity  in  illumination  desired. 

3.  Locate  a  luminant  or  unit  at  the  center  of  each  of  the  above  sub-divisions  at 
a  height  to  be  determined  from  Table  11.     Where  a  greater  intensity  is  required 
at  any  one  location  an  additional  unit  may  be  installed  or  the  regular  unit  may  be 
increased  in  intensity.     Obviously,  uniformity  procured  by  a  large  number  of  sub- 
divisions, will  be  attained  only  at  a  greater  cost. 

4.  Select  the  types  of  lamps  and  reflectors   to   suit   local   conditions;   tungsten, 
tantalum  and  carbon  lamps  are  available  and  are  commonly  used  for  interior  light- 
ing.   They  are  mentioned  above  in  the  order  of  their  efficiencies.     Focusing,  in- 
tensive and  extensive  reflectors  are  used  with  these  lamps. 

5.  Secure  from  the  manufacturer  of  the  reflector  the  distribution  curve  for  the 
particular  lamp  in  the  reflector. 

6.  Select  a  number  of  points  in  each  room  at  which  it  is  desired  to  check  the 
illumination.     The  number  of  such  points  and  their  location  is  dependent  entirely 
upon  the  accuracy  required  and  upon  the  local  conditions. 

7.  Measure  the  horizontal  and  vertical    distance   from    each   point    selected   to 
each  of  the  adjacent  luminants.     The  illumination  obtained  from  a  luminant  dis- 
tant from  the  point  in  question,  and  out  of  its  immediate  sphere,  may  be  neg- 


lected,  except  where  the  intensity  of  illumination  required  is  low  and  the  units 
are  large  and  widely  spaced. 

8.  From  Table  2  determine  the  intensity  from   each  unit    (considered  as  one 
candle  power),  in  foot  candles  at  the  point  in  question.     The  angle  between  the 
light  ray  and  a  line  perpendicular  to  the  plane  of  the  object  illuminated  is  also 
given  in  Table  2.     This  angle  applied  to  the  curve  of  distribution  for  the  lamp 
and   reflector  will   determine  the  total  candle  power  applied  by  the  unit.     Multi- 
ply the  intensity  in  foot  candles,   secured  above  for  one  candle  power,  by  the 
number   of   candle    power    projected    from  the   luminant  in   order  to   obtain  the 
number  of  foot  candles  from   one  unit  upon  the  point  in  question. 

9.  Treat  each  adjacent  unit  the  same,  and  sum  the  foot  candles  for  the  point 
in  question.     If  lower  than  the  assumed   value   it  will  be  necessary  to   choose 
larger  units  or  closer  spacing. 

10.  Tables  3  to  8  inclusive  give  the  intensity  direct  for  Mazda  lamps  in  Holo- 
phane  reflectors.     The  use  of  these  tables  will  reduce  the  calculation  materially. 

11.  Table  9  gives  the  approximate  co-efficients  of  reflection  from  wall  papers; 
that  is,  the  amount  of  reflected  light  expressed  as  a  proportion  of  the  total  light 
received  by  the  surface.    These  figures  are  based  on  the     use     of     incandescent 
lamps. 

12.  Table  10  gives  the  average  increase     in     illumination  over  the  calculated 
value  due  to  reflection  from  the  ceiling  and  walls. 


13.  Table  11  gives  the  approximate  height  of  lamps  above  the  plane  to  be  il- 
luminated in  order  to  secure  uniform  illumination. 

14.  From  Table  12  determine  the  number  of  outlets  required  and  the  amount 
of  current  to  be  carried  in  different  parts  of  the  system. 

15.  Table  16  may  then  be  consulted  to  determine  the  size  of  wire  required  to 
carry  with  safety  the  current  in  the  different  parts  of  the  system. 

16.  Table  14  may  then  be  consulted  to  determine  the  size  of  wire  required  to 
maintain  the  voltage  of  the  lamps  between  the  limits  of  the  rating  of  the  lamp. 
The  table  shows  values  for  one  volt  drop;   for  two   volts    drop   use   double   the 
values  given. 

17.  The  cost  of  producing  the  light  may    be    approximated     by     reference     to 
Tables  15  to  18  inclusive. 

SHORT        18.     A  shorter  but  less  accurate   method   of   computing   illumination 

METHOD      than  the  "point  by  point"  method  just  described  is  based  on  the  fact 

that   a    certain    definite    quantity    of    light  is  required  to  illuminate  one  square 

foot  of  surface  with  an  intensity  of  one  foot  candle.     This  unit  is  known  as  the 

"lumen." 

19.     When  a  lamp  is  capable  of  illuminating  400  square  feet  with  an  average 
intensity  of  one  foot  candle  it  may  be  rated  at  400  (effective)  lumens. 

7 


20.  To  find  the  number  of  lamps  needed  for  a  given  installation  multiply  the 
area  in  square  feet  by  the  required  intensity  in  foot  candles,  thus  obtaining  the 
total  lumens,  and  then  divide  this  product  by  the  effective  lumens  per  lamp,  i.  e., 
the  lumens  per  lamp  reaching  the  plane  to  be  lighted.    See  Table  19. 

21.  The  values  given  in  Table  20  under  "Mazda"  lamps  are  for  ordinary  light- 
in?  with  "Mazda"  lamps  and  clear  high  efficiency  reflectors  in  rooms  with  average 
or  dark  walls  and  ceiling.     Where  both  ceiling  and  walls  are  very  light  the  num- 
ber of  lumens  may  be  increased  by  25  per  cent, 

22.  Where  the  light  from  a  single  lamp  must  be  spread  over  a  relatively  great 
area,  it  is  advisable  to  use  an  extensive  form  of  reflector. 

23.  Where  each  unit  lights  a  relatively  small  area  or  where  more  concentration 
is  desired,  the  intensive  reflector  should  be  used. 

24.  Where  an  intensive  light  on  a  small  area  directlv  below  the  lamp  is  de- 
sired, a  focusing  reflector  is  used.     This  type  is  largely  used  in  show  windows, 
high  narrow  vestibules  and  other  rooms  having  unusually  high  ceilings. 


TABLE  No.  1                                                *Foot  Candles 
Required  Intensity  of  Illumination                                  Required 

Auditoriums,   Theatres    1.00  —  3.0 

Bookkeeping    3.00  —  5.0 

Corridors,   Halls    . 50  — .  1.0 

Depots,   Assembly  Halls  and  Churches 75  —  1.5 

Drafting  Rooms   5.00  —  10.0 

Desk    Lighting    2.00  —  5.0 

Engraving    5.00  —  10.0 

Factories,  General,  where  individual  drops  are  used 4.00  —  5.0 

Factories,   Complete,   no   individual   drops 4.00  —  5.0 

Hotel  Halls    1.00  —  1.5 

Hotel   Rooms 2.00  —  3.0 

Offices    ( Waiting  Rooms) 1.25  —  2.5 

Offices    (Private)    2.00  —  3.0  t 

Offices    (General)     3.00—  4.0 

Offices   (where  desk  lights  are  used) 1.50  —  2.5 

Post   Offices 2.00  —  5.0 

Reading     1.00  —  3.0 

Residences    1.00  —  3.0 

Stores   (Light  Goods) 2.00  —  3.5 

Stores  (Dry  Goods) 4.00  —  6.0 

Stores    (Clothing)     4.00  —  7.0 

Store  Windows 5.00  —  20.0 

Scnool   Rooms    2.00  —  3.0 

Saloons,  Cafes,  depending  on  effects 2.00  —  5.0 

Stations   (Waiting  Rooms) 1.50  —  2.5 

Train  Sheds 1.50  —  2.0 

Warehouses    1.50  —  2.0 

*A  foot-candle  is  the  intensity  of  illumination    received   by   a   surface   held   normal   to  the 
direction  of  the  light  at  a  distance  of  one  foot  from  a  light-source  of  1  candle-power. 

9 


TABLE  No.  2 


1  Candle-Power. 


Angle  Between  Liyht  Bay  and  Line  Perpendicular  to  Flan*  Illuminated 


DJtOO 

02210 

00764 

.00064 

78°42- 

6 

0°0' 
.04000 

11°19' 
.03771 

21°48' 
.03202 

:,o  ti- 
.02522 

U'W 

01504 

45°  0' 
.01414 

.01050 

.00785 

.00595 

.00458 

.00358 

,04211 

.0*211 

.00185 

.00152 

00126 

.00106 

73°37' 
.00090 

74°29- 
.OQ077 

75°16' 
.00066 

75°66' 
.00057 

*' 

.02778 

02673 

.02372 

.01987 

.01600 

01260 

.00982 

.00766 

.00600 

00474 

.00378 

.00305 

.00249 

.00205 

.00170 

.00142 

.00120 

.00102 

.00088 

00(176 

.00066 

f  7 

.02041 

.01980 

.01814 

.01585 

.01336 

.01100 

.test] 

.00722 

.00583 

.00473 

00385 

.00316 

.00261 

.00218 

00183 

.00154 

.00131 

.00119 

68M5' 
.00097 

00034 

.00074 

a  « 

01563 

.01627 

.01427 

.01283 

.01118 

00953 

.oosoo 

00667 

.00552 

.00458 

.00381 

.00318 

.00267 

.00225 

.00191 

.00163 

.00140 

00121 

.00105 

.00091 

.00080 

'T  9 

01235 

.01212 

.01148 

.01054 

.00943 

0082C 

.00711 

.00607 

.00615 

.00437 

00370 

00314 

00267 

.00228 

.00196 

00168 

.00146 

.00126 

00110 

.00*01 

.00085 

g>10 

.01000 

.00985 

11«19' 
.00»43 

.00879 

.00801 

.00716 

.00631 

.00550 

.00476 

.00411 

00354 

.00305 

,002*1 

.00227 

.00196 

.00171 

.00149 

.00130 

.ooiir, 

.00101 

.00089 

iu 

00826 

.00816 

.00787 

.00742 

.00686 

.00623 

.00559 

.00496 

.00437 

.00383 

.00335 

.00292 

.00255 

.00223 

.00195 

.00171 

.00150 

.00132 

.00117 

.00104 

.00092 

J" 

.00694 

.00687 

.00668 

.00634 

.00593 

.OO.V16 

.00497 

.00448 

.00400 

.00356 

.00315 

.00278 

.00246 

.00217 

.00191 

.00169 

.00150 

.00133 

.00119 

.00106 

.00094 

;» 

.00592 

.00587 

.00571 

.00547 

.00517 

.00481 

.00447 

.00404 

.00366 

.00329 

.00295 

.00263 

.00235 

00209 

00187 

00166 

.00148 

.00133 

.00119 

.00106 

.00096 

}M 

.00510 

.00506 

.00495 

.00477 

00454 

.00426 

.00396 

.00365 

.00334 

.00304 

.00275 

.00248 

.00223 

.00201 

.00180 

.00162 

.00146 

.00131 

.0011* 

.00107 

.00096 

S» 

.00444 

.00442 

.00433 

.00419 

.00401 

.00380 

.00356 

.00331 

.00305 

.00280 

.00256 

.00233 

.00212 

.00192 

.00174 

00157 

.00142 

.00129 

00117 

.00106 

.00096 

!• 

.00391 

.00388 

.00382 

.00371 

.00357 

.00339 

.00321 

.00300 

.00280 

.00259 

.00238 

.00219 

.00200 

00183 

.00167 

.00152 

.00138 

00126 

.00116 

.00105 

.00095 

317 

.00346 

00344 

.00339 

.00331 

.00319 

.00306 

.00290 

.00274 

.00256 

.00239 

.00222 

.00205 

.00189 

00174 

.00159 

00146 

00134 

00122 

.00112 

.00103 

.00094 

I" 

.00309 

.00307 

.00303 

.00297 

.00287 

.00276 

.00264 

.00250 

.00236 

.00221 

.00206 

.00192 

.00178 

.00165 

00152 

00140 

00129 

.00119 

00109 

.00100 

.00092 

19 

00277 

.00276 

.00273 

.00267 

00260 

00261 

.00240 

.00229 

.00217 

.00206 

.00192 

.00180 

.00167 

.00156 

00145 

.00134 

00124 

00115 

.00106 

.00098 

.00090 

20 

.00250 

00249 

.00246 

00242 

.00236 

00228 

00219 

00210 

.00200 

00190 

.00179 

.00168 

.00158 

.00147 

00137 

.00128 

.00119 

.00111 

00103 

MOM 

.00088 

10 


TABLE  No.  3 

Horizontal  distinct  of  point  InTeittgited  In  feet  rram  point  directly  beneath  Unit. 


2.67 
0.61 
1.04 
1.71 

0.72 
1.18 

2.64 
1.70 

2.58 

2.12 

1.35 

O.S 

0.48 

0.30 

0.20 

0.14 

0.10 

0.09 

0.06 

0.05 

0.04 

0.03 

0.03 

0.02 

0.02 

0.01 
0.01 

0.0 
0.0 

?si; 

0.24 

0.32 
0.53 

0.24 

0.32 
0.62 

0.32 
0.52 

0.32 
0.52 

0.3 
0.5 

0.2 
0.5 

0.28 
0.46 

0.25 
0.40 

0.2 
0.3 

o.n 

0.28 

0.13 
0.21 

0.11 
0.17 

0.08 
0.13 

0.06 
0.11 

0.05 
0.09 

0.04 
0.07 

0.04 
0.06 

0.03 
0.05 

0.02 
0.04 

0.03 

0.01 
0.02 
0.03 

0.0 

0.0 
0.0 
0.0 

1$ 

I  III 

Ilil 

0.26 
0.43 

0.26 

0.26 

0.26 

0.2 

0.2 

0.24 

0.22 

0.2 

0.17 

0.14 

0.11 

0.09 

0.07 

0.06 

0.05 

0.04 

0.03 

0.03 

0.02 

0.0 

0.13 

0.13 

0.13 

0.12 

0.1 

0.1 

0.11 

0.10 

0.10 

0.09 

0.0.7 

O.OG 

0.06 

0.04 

0.04 

0.03 

0.03 

0.02 

0.02 

0.02 

0.0 

?is3 

0.35 

0.35 

0.35 

0.35 

0.35 

0.3 

0.33 

0.31 

0.29 

0.26 

0.23 

0.19 

0.15 

0.12 

0.11 

0.09 

0.07 

0.06 

0.05 

0.04 

0.0 

0.11 

0.11 

0.11 

0.10 

0.10 

0.10 

0.10 

0.09 

0.09 

0.08 

0.07 

0.06 

0.06 

0.05 

0.04 

O.P3 

0.    3 

0.02 

0.02 

0.02 

0.0 

n*®* 

0.30 

0.30 

0.29 

0.29 

0.29 

0.29 

0.29 

0.28 

0.26 

0.24 

0.21 

0.18 

0.16 

0.13 

0.11 

0.09 

0.    7 

0.07 

0.05 

0.05 

0.0 

*  o  ®  E. 

0.09 
0.16 
0.25 

0.09 
0.16 
0.26 

0.09 
0.16 
0.25 

0.09 
0.16 
0.25 

0.09 
0.16 
0.25 

0.09 
0.15 
0.25 

0.08 
0.15 
0.25 

0.08 
0.14 
0.24 

0.08 
0.14 
0.23 

0.07 
0.13 
0.21 

0.07 
0.12 
0.19 

0.06 
0.11 
0.18 

0.05 
0.10 
0.15 

0.05 
0.08 
0.14 

0.04 
0.07 
0.12 

0.03 
0.06 
0.10 

0.    3 
0.    6 
0.    8 

0.02 
0.04 
0.07 

0.02 
0.03 
0.06 

0.02 
0.03 
0.05 

0.0 
0.0 
0.0 

0.13 
0.22 

0.22 

0.22 

0.22 

0.22 

0.22 

0.22 

0.21 

0.20 

0.19 

0.18 

0.17 

0.15 

0.14 

0.12 

0.10 

0.08 

0.07 

0.06 

0.05 
0.02 

0.0 

0.0 
0.0 

P  °^3 

IS* 

0.13 

0.13 

0.13 

0.13 

0.13 

0.13 

0.13 

0.13 

0.13 

0.13 

0.13 

0.1? 

0.11 

0.11 

0.10 

0.09 

0.08 

0.08 

0.07 

0.02 
0.04 

0.06 

o!o 

0.0 
0.0 

II? 
ss$ 

0.07 
0.12 

0.07 
0.12 

0.07 
0.12 

0.07 
0.12 

0.07 
0.12 

0.07 
0.12 

0.07 
0.12 

0.07 
0.12 

0.07 
0.12 

0.07 
0.12 

0.07 
0.11 

0.07 
0.11 

0.06 
0.11 

0.06 
0.10 

0.06 
0.09 

0.06 
0.09 

0.05 
0.08 

0.05 
0.08 

0.04 
0.07 

0.04 
0.06 

0.0 
0.0 

0.04 
0.11 

0.04 

0.04 

0.04 

0.04 

0.04 

0.04 

0.04 

0.04 

0.04 

0.03 

0.03 

0.03 

0.03 

0.03 

0.03 

0.03 

0.02 

0.02 

0.02 

0.0 

an 


" 


:.;  40- wait.  1.25  w.  p.  c.;  80-wa 


11 


TABLE  No.   4 


Horizontal  distend*  of  pofnt  Investigated  fn  fctt  from  point  directly  beneath  Fnit. 


4 
6 
• 
1 

a  8 
*f 

2  w 

5* 

8.00 

7.64 

6.80 

5.95 

3.94 

2.18 

1.29 

0.79 

0.51 

0.35 

0.25 

0.18 

0.14 

0.11 

0.09 

0.07 

0.08 

0.05 

0.04 

O.Uli 
0.03 
0.05 

0.02 
0.03 
0.05 

!!!!„ 
r«=i 

3.00 
5.12 
8.49 

2.96 
4.90 
9.21 

2.82 
4.51 
8.56 

2.49 
4.18 

1.95 

3.58 

1.40 
2.52 

0.87 
1.60 

0.57 
1.01 

0.40 
0.67 

0.26 
0.47 

0.19 
0.33 

0.14 
0.24 

0.11 
0.18 

0.10 
0.14 

0.07 
0.11 

0.06 
0.09 

O.OS 
0.07 

0.04 
0.06 

11.  Oil 
0.05 

0.03 
0.04 

0.03 
0.04 

3.58 

3.45 

3.22 

3.03 

•2.80 

2.37 

1.75 

1.20 

0.81 

0.57 

0.42 

0.30 

0.23 

0.18 

0.14 

0.11 

0.09 

0.07 

0.06 

0.05 

0.04 

1.53 

1.51 

1.47 

1.44 

1.30 

1.12 

0.90 

0.71 

0.53 

0.37 

0.2» 

0.20 

0.16 

0.12 

0.09 

0.07 

0.06 

0.06 

0.05 

0.04 

0.03 

H?Ja 

5?3  liW 

2.00 
3.71 
0.93 
1.58 
2.93 

3.68 
0.92 
1.65 
2.90 

0.91 
1.49 

0.89 
1.43 

0.86 
1.37 

1.80 

1.30 

0.72 
1.26 

0.63 
1.13 

0.52 
0.96 

0.43 

0.78 

0.33 
0.61 

0.27 
0.48 

0.19 

0.3< 

0.18 
0.29 

0.12 
0.23 

0.10 
0.18 

0.09 
0.15 

0.07 
0.12 

0.09 

0.06 
0.10 

0.07 

0.05 
0.09 

0.06 

0.04 
0.07 

°lrs| 
*  3  B  CO^ 

:srg|i 

an"  ",a 

°*  i*s 

g.-3~o 

s.aSS 

•|frt 

rM 

0.75 
1.28 

0.62 

0.75 
1.26 

0.62 

0.74 

1.Z2 

0.61 

0.73 
1.18 

0.71 
1.13 

0.67 

0.62 

0.57 

0.4» 

0.42 

0.3S 

0.28 

0.22 

0.18 

0.14 

0.11 

0.13 

0.09 
0.11 

0,08 
0.09 

0.06 
0.07 

0.05 

0.05 

<u 

i. 

3  is 

1" 

f>* 

s» 

17 
18 
» 

at 

i.M 

1.96 
0.52 
0.89 
1.64 

1.94 
0.52 
0.88 

0.51 
0.86 

0.51 
0.84 

0.50 
0.81 

0.48 
0.78 

0.46 
0.75 

0.44 
0.72 

0.40 
0.70 

0.37 

0.6S 

0.32 
0.59 

0.28 
0.52 

0.24 
0.44 

0.20 

o.ss 

0.18 
0.30 

0.14 
0.24 

0.11 

0.20 

0.10 
0.17 

0.08 
0.14 

0.07 
0.12 

0.09 
0.17 
0.05 
0.10 

0.7S 

0.7S 

0.74 

0.72 

0.70 

0.67 

0.65 

0.63 

0.61 

0.59 

0.55 

0.49 

0.43 

0.37 

0.32 

0.28 

0.22 

0.19 

0.18 

0.13 

0.12 

ft  a*ne  «  >> 

S??3& 
t?J% 

~n  Oo  " 

Cglfl 

0.38 
0.65 

1.21 

0.3S 
0.65 

0.38 
0.64 

0.38 
0.62 

0.37 
0.61 

0.36 
0.59 

0.36 
0.57 

0.34 

0.55 

0.32 
0  54 

0.31 
0  52 

0.28 
0.5» 

0.26 
0.46 

0  .  L1  It 
0.42 

0.20 
0.37 

0.18 
0.32 

0.18 
0.28 

0.13 

0.24 

0.11 
0.20 

0.09 
0.17 

0.08 
0.14 

0.07 
0.12 

0.33 
0.57 
1.05 

0,33 
0.57 
1.05 

0.33 
0.56 
1.04 

0.33 
0.55 
1.02 

0.32 
0.53 
1.00 

0.32 
0.52 
0.98 

0.31 
0.50 
0.95 

0.30 
0.49 
0.92 

0.29 
0.48 
0.89 

0.28 
0.46 
0.87 

0  26 
0.45 
0.84 

0.24 
0.43 
0.82 

0.22 
0.40 
0.79 

0.2» 
0.36 
0.71 

.18 
i  .32 
.63 

0.16 

0.28 
0.55 

0.14 
0.24 
0.48 

0.12 
0.21 
0.41 

0.10 
0.18 
0.38 

0.09 
0.15 
0.31 

0.08 
0.13 
0.26 

0.50 
0.93 

0.50 
0.92 

0.49 
0.91 

0.48 
0.90 

0.47 
0.89 

0.46 
0.87 

0.45 
0.85 

0.43 
0.82 

0.42 

0.80 

0.41 
0.77 

0.40 
0.75 

0.39 
0.73 

0.37 
0.72 

».34 
0.68 

.31 

0.28 
0.55 

0.25 
0.49 

0.22 
0.42 

0.19 
0.37 

0.18 
0.32 

0.08 
0.14 
0.28 

0.44 
0.82 

0.44 
0.82 

0.43 
0.81 

0.43 

0.80 

0.42 
0.79 

0.41 
0.77 

0.40 
0.75 

0.39 
0.73 

0,38 
0.71 

0.37 
0.70 

0.36 
0.68 

0.35 
0.66 

0.34 
0.65 

0.32 
0.63 

0.30 
0.59 

0.27 
0.54 

0.25 

0.49 

0.22 
0.43 

0.19 

').:;« 

.17 
.33 

0.15 

0.29 

ri'^S 
"£S*  = 

R 

reft 

0.23 
0.39 
0.73 

0.23 
0.39 
0.73 

0.23 
0.39 
0-.73 

0.23 
.0.38 
0.72 

0.23 
0.37 
0.70 

0.23 
0.37 
0.69 

0.22 
0.36 
O1.  68 

0.22 
0.35 
0.66 

0.22 
0.34 
0.65 

0.21 
0.34 
0.63 

0.20 
0.33 
0.61 

0.19 
0.32 
0.60 

0.18 
0.31 
0.59 

0.17 
0.30 
0.58 

0.16 
0.28 

».5«  j 

0.14 
0.26 
0.52 

0.13 
0.24 

0.4S 

0,12 
0.22 
0.43 

0.11 
0.19 
0.38 

.09 
.17 
.34 

0.09 
0.15 
0.30 

0.35 
0.66 

0.21 
0.35 
0.66 

0.21 
0.35 

0.65 

0.21 
0.34 
0.64 

0.21 
0.34 
0.63 

0.20 
0.33 
0.62 

0.20 
0.32 
0.61 

0.20 
0.32 
0.60 

0.19 
0.31 
0.59 

0.19 
0.30 
0.67 

0.18 
0.30 
0.56 

0.1S 
0.29 
0.65 

Q.17 
0.28 
0.53 

0.16 
0.27 
0.52 

0.15 
0.26 
0.51 

0  .  !  4 
0.25 
0.49 

0.13 
0.23 
0.46 

0.12 
0.22 
0.42 

0.11 
0.20 

11.1:9 

.10 
o!35 

0.09 
0.16 
0.30 

0.19 
0.3J 
0.59 

0.19 
0.32 
0.59 

0.19 
0.32 

0.59 

0.19 
0.31 
0.58 

0.19 
0.31 
0.58 

0.19 
0  30 
0.57 

0.18 
0.29 
0.56 

0.18 
0.29 
0.55 

0.18 
0.28 
0.53 

0.17 
0.27 
0.52 

0.17 
0.27 
0.61 

0.16 
0.26 
0.50 

0.16 
0.26 
0.49 

0.15 
0.25 
0.48 

0.14 
0.24 
0.47 

0.13 
0.24 
0.46 

0.12 
0.22 
0.44 

0.12 
0.21 
0.41 

0.11 
0.19 
0.38 

0.10 
0.17 
0.34 

0.09 
0.16 
0.31 

NOTE—  Thi*  table  U  based  on  the  following  efficiencie*  :  100-watt,  l.aO  w.p.c.;  ISO-watt,  1>20  w.p.c.;  250.watt,  1.15  w.p.c. 

12 


TABLE  No.  5 


Horizontal  distinct  of  point  investigated  in  feet  from,  point  directly  beneath  Unit 


1.94 

1.77 

0.01 

0.01 

0.01 

.... 

ft 

5.40 
1.24 
1.96 
3.46 

4.78 
1.17 
1.81 
3.20 

0.97 
1.56 
2.69 

0.73 
1.21 
2.05 

0.83 
1.33 

0.50 
0.78 

0  30 
0.48 

0.20 

0.31 

0.14 
0  20 

0  09 
0.12 

0.06 
0.09 

0.05 
0.07 

0.04 
0.05 

0.02 
0.03 
0.04 

0.02 
0.02 
0.03 

0.01 
0.02 
0.03 

0.01 
0.02 
0.02 

0.01 
0.01 
0.02 

0.01 
0.01 
0.02 

0.01 
0.01 
0.01 

0.01 
0.01 

0.01 

0.87 

t.M 

0.73 

0.59 

0.45 

0.33 

0.23 

0.16 

0.11 

0.08 

0.06 

0.04 

0.03 

0.03 

0.02 

0.02 

0.01 

0.01 

0.01 

0.01 

0.01 

2.40 

I.S6 

1.98 

1.62 

1.23 

0.87 

0.54 

0.36 

0.25 

0.17 

0.11 

0.09 

0.06 

0."-, 

0.04 

0.03 

0.03 

0.02 

0.02 

0.02 

0.01 

7 

1.00 

1.76 

0.96 
1.69 

0.89 
1.55 

0.76 
1.29 

0.64 

1.07 

0.50 
0.81 

0.36 

0.25 

0.20 

0.12 

0.09 

0.07 

0.06 

0.04 

0.03 

0.02 

0.02 

0.02 

0.02 

0.01 

0.01 

3    8 

a.  49 

0.77 

0.48 

0.44 

0.39 

0.34 

0.27 

0.21 

0.17 

0.13 

0.10 

0.08 

0.06 

o.or, 

0.04 

0.03 

0.02 

0.02 

0.02 

0.01 

0.01 

0.01 

£   * 

a 

0.38 

o..;o 
1.08 

0.37 
0.59 
1.04 

0.35 
0.56 
0.98 

0.33 
0.51 
0.88 

0.28 

0.46 

0.24 
0.40 

0.19 
0.33 

0.16 
0.27 

0.13 
0.21 

0.10 
0.17 

0.08 
0.12 

0.06 
0.09 

0.05 
0.07 

0.04 
0.06 

0.03 
0.04 

0.03 
0.03 

0.02 
0.03 

0.02 
0.02 

0.01 
0.02 

0.01 
0.02 

0.01 
0.02 

I 

In 

0.87 

0.40 

0.71 

0.84 

0.40 
0.69 

0.81 

0.3S 
0.67 

0.74 

0.37 
0.63 

till 

0.34 
0.58 

0.59 

0.30 
0.51 

0.27 
0.45 

0.23 
0.39 

0.20 
0.33 

0.17 

0.27 

0.14 

0.22 

'0.11 
0.17 

0.08 
0.13 

0.07 
0.11 

0.06 
0.09 

0.05 
0.07 

0.04 
0.06 

0.03 
0.04 

0.02 
0.04 

0.02 
0.03 

0.01 
0.02 
0.03 

H» 

0.21 
0.34 
0.60 

0.21 

0.34 

0.20 
0  33 
0.57 

0.19 
0.31 
0.54 

0.19 
0.29 
0.50 

0.17 
0.27 
0.46 

O'.IS 
0.24 
0.40 

0.13 
0.22 
0.36 

0.11 
0.19 
0.31 

0.10 
0.16 
0.26 

0.08 
0.13 

0.21 

0.07 
0.11 

0.17 

0.06 
0.09 
0.16 

0.05 
0.  7 

'i.  I 

•0.04 
0.06 
0.09 

0.03 
0.05 
0.07 

0.03 
0.04 
0.06 

0.02 
0.03 
0.05 

0.02 
0.03 
0.04 

0.02 
0.03 
0.04 

0.01 
0.02 
0.'03 

13 

5 

0.19 
0.29 
0.51 

0.19 
0  29 
0.50 

0.18 
0.28 
0.49 

0.17 
0.27 
0.47 

0.16 
0.25 
0.44. 

0.15 
0.24 
0.41 

0.13 
0.22 
0.37 

0.12 
0.32 

0.10 
0.17 
0.29 

0.09 
0.15 

O.OS 
0.13 
0.21 

0.07 
0.11 
0.18 

IMI-; 
0.09 
0.15 

0.  5 

0.  8 
0.  2 

0.04 
0.07 
0.10 

0.04 
0.06 
0.08 

0.03 
0.04 

0.07 

0.03 
0.04 
0.06 

0.02 
0.03 
0.05 

0.02 
0.03 
0.04 

0.02 
0.02 
0.04 

?14 

0.16 
0.25 
0.44 

0.16 
0.25 
0.43 

0.15 
.0.24 
0.42 

0.15 
0.23 
0.41 

0.14 

0.22 
0.38 

0.13 
0.21 
0.36 

0.12 
0.20 
0.33 

0.11 
0.18 
0.30 

0.10 
0.16 
0.27 

0.09 

0.14 
0.24 

0.08 
0.12 
0.20 

0.07 
0.11 
0.18 

0.06 
0.09 
0.15 

0.  5 
0.  8 
0.'  3 

0.04 
0.07 
0.11 

0.04 
0.06 
0.09 

o!  5 

0.  7 

0.  3 
0.  4 

0.  6 

0.02 
0.03 
0.05 

0.02 
0.03 
0.04 

0.02 
0.03 
0.04 

|,5 

O.H 
0.22 
0.38 

0.14 

0.22 

n.  :•.'•. 

0.13 
0.21' 
0.37 

0.13 
0.21 
0.36 

0.  K' 

0  20 
0.34 

O.H 
0.18 
0.«2 

O.liT 
0.17 
0.30 

0.10 

O.K. 
0.27 

0.09 
0.15 
0.25 

0.08 
0.13 
0.23 

0.07 
0.12 
0.20 

0.06 
0.11 

0.18 

0.06 
0.09 
0.15 

0.  5 
0.  8 
0.  3 

0.04 
0.07 
0.11 

0.04 
0.06 
0.09 

0.  3 
0.  5 
0.  8 

0.  3 
0.  4 
0.  7 

0.02 
0.03 
0.05 

0.02 
0.03 
0.0.1 

0.02 
0.03 
0.04 

i  16 

0.19 
0.34 

019 

o.  ::.: 

0  19 
0.32 

0.18 
0.31 

0.17 
0.30 

0.16 

0.28, 

0.16 
0.27 

0.15 
0.25 

0.14 

0.23 

0.13 
0.21 

0.11 
0.19 

0.10 
0.16 

0.09 

0.15 

0.  8 
0.  3 

0.07 
0.11 

0.06 
0.10 

0.  5 
0.  8 

0.  5 
0.  7 

0.04 
0.06 

0.03 
0.05 

0.03 
0.04 

*  17 

0.17 
0.30 

0.17 
0.29 

0.17 
0.29 

0.16 
0.2S 

0.16 
0.27 

0.15 
0.26 

0.14 
0.24 

0.13 
0.23 

0.13 

0.22 

0.12 
0.20 

0.11 
0.18 

0.10 
0.16 

0.09 
0.14 

o!  2 

0.07 

0.06 
0.10 

0.  5 
0.  9 

0.  5 

0.  7 

0.04 
0.06 

0.03 
0.05 

0.03 
0.05 

18 

0.10 
0.15 
0.27 

0.10 
0.15 
0.27 

0.09 
0.15 
0.26 

0.09 
0.14 
0.25 

0.09 
0.14 
0.24 

0.09 
0.13 
0.23 

575i 

0.13 
0.22 

0.08 
0.12 
0.21 

0.07 
0.12 

0.20 

0.07 
0.11 
0.18 

0.06 
0.10 
0.17 

0.05 
0.09 
0.15 

0.05 
0.08 
0.14 

0.  6 
0.  7 
0.  2 

o.o.l 
0.07 

o.n 

0.04 
0.06 

0.  3 
0.  5 
0.09 

0.  3 
0.  5 
0.  8 

0.03 
0.04 
0.06 

0.02 
0.04 
0.06 

0.02 
0.03 
0.06 

19 

0.14 

0.24 

•i  1  4 

0.24 

0.13 
0.24 

0.13 
0.23 

0.13 
0.22 

0.12 
0.21 

0.12 

o.;o 

O.il 
0.(9 

0.11 
0.18 

0.10 
0.17 

0.09 
0.16 

t'.tt 

t.il 

0.08 
0.13 

o!  2 

0.0« 
0.10 

0.06 
0.10 

0.05 
0.09 

0.05 
0.08 

o.o* 

1.01 

0.04 
0.06 

0.03 

o.or. 

X 

0.12 

0.22 

g  ij 

0.22 

0.12 

0.21 

0.12 
0.21 

0.11 

0.20 

0.11 
0.19 

0.11 
0.1S 

0.10 

0.17 

0.10 

0.17 

0.09 
0.16 

0.09 

0.15 

0  .  0  < 
0.14 

0.08 
0.13 

0.07 
0.12 

0.0« 

0.10 

0.06 

0.09 

0.05 
0.08 

0.05 
O.OS 

0.04 
0.07 

0.04 

o.os 

0.03 

tl.fr, 

-This  table  is  based  on  the  following  efficiencies :  25-watt,  1 .33  w.p.c. ;  40-watt,  1 .25  w.p.c.;  00-watl.  1.20  w  p  c 


13 


TABLE  No.  6 


Horizontal  distance  of  point  Inreitlgtted  in  feet  from  point  directly  beneath  Unit. 


7.6S 

6.90 

5.25 

3.47 

1.92 

1.08 

0.65 

0.35 

0.23 

0.15 

0.11 

0.10 

0.07 

0.06 

0.05 

0.04 

0.0.1 

0.03 

0.02 

0.02 

0.02 

:•  :;  .  i  •: 

21.11 

16.02 

10.11 

5.96 

3.43 

1.  8 

1.21 

0.79 

0.54 

0.38 

0.28 

0.21 

0.16 

0.13 

0.10 

0.09 

0.07 

0.06 

0.05 

0.04 

t 

8.49 

8.00 

6.76 

5.04 

3.39 

2.20 

1.  9 

0  88 

0.58 

0.40 

0.29 

0.21 

0.16 

0.13 

0.10 

0.08 

0.07 

0.05 

0.05 

0.04 

0.03 

|SH 

• 

3.41 
6.88 
It.  11 

3.24 
5.66 

2.87 
5.03 

2.34 
4.09 

1.76 
3.09 

1.30 

2.20 

0.  4 
1.  3 

0.57 
1.03 

0.38 
0.71 

0.25 
0.48 

0.18 
0.35 

0.14 
0.26 

0.10 

o.:o 

0.08 
0.16 

0.07 
0.12 

0.05 
0.10 

0.04 
0.08 

0.04 
0.07 

0.03 
0.06 

0.03 
0.05 

0.02 
0.04 

0.07 

Jp°rg! 

s  =i* 

2.51 

2.40 

2.24 

1.93 

1.63 

1.19 

0.  9 

0.65 

0.46 

0.31 

0.21 

0.16 

0.13 

0.10 

0.08 

0.06 

0.05 

0.04 

0.04 

0.03 

0.03 

-5=^5 

7.55 
1.92 

7.32 
1.88 

6.70 
1.74 

6.79 
1.55 

4.66 
1.33 

3.55 

2.  7 

1.95 

1.42 

1.04 

0.75 

0.56 

0.43 

0.33 

0.2* 

0.21 

0.17 

0.14 

0.12 

0.10 

0.08 

(ttJ  •"•'">» 
£3»<j? 

£.• 

1.50 
2.62 

4.57 

1.48 

2.67 
4.48 

1.3 
2.4 
4.2 

1.27 
2.23 
3.90 

1.13 
1.98 
3.43 

0.96 
1.67 
2.89 

0.  8 
1.  7 
2.  6 

0.65 
1.09 
1.89 

0.51 
0.8T 

1.50 

0.40 
0.68 
1.18 

0.30 
0.53 

0.92 

0  23 
0.41 

0.72 

0.16 
0.32 
0.56 

0.13 
0  25 
0.44 

0.10 
0.20 
0.35 

0.08 
0.16 
0.28 

0.20 
0.07 
0.13 
0.23 

0.16. 
0.05 
0.11 

0.19 

0.14 
0.04 
0.09 
0.16 

0.11 
0.04 
0.07 
0.13 

0.10 
0.03 
0.06 

0.11 

i  3  °r  - 
l«jl 

;=s*§ 

§  10 

5" 

1.23 
2.12 
3.70 

1.21 
2.09 
3.64 

1.1 
2.0 
3.4 

1.06 
1.86 
3.25 

0.97 
1.69 
2.94- 

0.84 
1.48 
2.56 

0.  2 
1.  6 

2.  7 

0.61 
1.04- 

1.79 

0.49 
0.85 
1.46 

0.41 
0.69 

1.18 

0.33 
0.55 
0.9« 

0.25 
0.44 
0.77 

0.19 
0.35 
0.61 

0.15 
0.28 
0.49 

0.12 
0.22 
0.39 

0.09 
0.1S 

0.32 

0.07 
0.15 
0.26 

0.06 
0.12 
0.21 

0.05 
0.10 
0.18 

0.04 
0.08 
0.15 

0.04 
0.07 
0.13 

i&fr 
*!«!s 

s« 

1.75 
3.06 

1.73 
3.02 

1.6 

2.9 

1.57 
2.74 

1.45 
2.53 

1.20 

2.26 

1.  4 

1.  3 

0  97 

1.67 

0.81 
1.40 

0  67 
1.16 

0..56 
0.96 

0.46 
0.79 

0.37 
0.64 

0.30 
0.53 

0.24 
0.43 

0.20 
0.35 

0.  6 
0.  » 

0.13 
0.24 

0.11 

0.20 

0.09 
0.17 

0.08 
0.14 

?»!££ 
Nv-fr 

\  >2 

l!47 

l!46 

O.S 
1.4 

0.77 
1.34 

0.72 
1.26 

0.65 
1.15 

0.  8 
1.  2 

0.52 
0.90 

0.45 
0.77 

0.38 
0.66 

0.32 
0.55 

0.28 
0.46 

0.23 
0.38 

0.18 
0.31 

0.14 
0.26 

0.11 
0.21 

0.  9 
0.  » 

0.08 
0.15 

0.07 
0.12 

0.06 
0.10 
0.19 

o!o9 

0.16 

Ml 

S  is 

0.73 
1.25 
2.18 

0.72 
1.24 

2.17 

0.  7 
1.2 
2.1 

0.67 
1.16 
2.02 

1.91 

1.77 

1.  2 

1.43 

1.25 

1.07 

0.92 

0.78 

0.66 

0.56 

0.  8 

0.40 

0.  4 

0.29 

0.24 

0.20 

0.17 

Ml 

5> 

0.63 
1.08 
1.89 

l!o7 
1.87 

0.6 
1.0 

1.8 

0.58 
1.01 
1.77 

0.55 
0.96 
1.68 

0.51 
0.90 

1.57 

0.  7 
0.  3 

1.  + 

0.43 
0.75 
1.31 

0.38 
0.67 
1.17 

0.34 
0.59 

1.02 

0.30 
0.51 
0.89 

0.27 
0.44 
0.77 

0.22 
0.39 
0.66 

0.19 
0  33 
0.67 

0.  7 
0.  S 
0.  9 

0.14 
0  24 
O."41 

0.  2 
0.  0 
0.  5 

0.09 
0.17 
0.30 

0  OS 
0.15 
0.26 

o!l2 
0.22 

o!n 

0.19 

&l* 

I16 

0.94 
1.64 

0.94- 
1.64 

0.9 
1.6 

0.51 
0.87 
1.55 

0.49 
0.85 

1.48 

0.47 
0.81 

1.41 

0.  3 
0.  5 
1.  0 

0.40 
0.69 
1.20 

0.36 
0.63 
1.08 

0.32 
0.56 
0.96 

0.28 
0.49 
0.85 

0.26 
0.43 
0.75 

0.22 
0.38 
0.65 

0.19 
0.33 
0.56 

0.  7 
0.  9 
0.  9 

0.15 
0.24 
0.42 

0.  2 
0.  1 

0..  7 

0.10 
0.18 
0.31 

0.08 
0.15 
0.27 

0  OS 
0.13 
0.24 

0.11 
0.20 

??ti§ 
»*'j%*i 

a  ie 

0    4$ 
0.83 
1.45 

0.48 
0.82 
1.44 

0.4 
0.8 
1.4 

0.45 
0.79 
1.37 

0.43 
0.76 
1.32 

0.41 
0.72 
1.26 

0.  9 
0.  8 
1.  8 

0.36 
0.63 

1.12 

0.33 
0.58 
1.00 

0.30 
0.52 
0.91 

0.27 
0.47 
0.81 

0.24 
0.42 

0.72 

0.21 
0.37 

0.63 

0.19 
0  32 
0.56 

11 
0.  9 

0  15 
0.25 
0.43 

0.13 
0.22 
0.37 

0.11 
0  19 
0.32 

0.09 
0  16 
0.28 

0.  08 
0.14 
0.26 

o!l2 
0.21 

17 

0.42 
0.73 
1.28 

0.73 
1.27 

O.T 
1.2 

0.41 
0.70 

1.22 

0.39 
0.68 

1.18 

».  H7 
0.65 
1.13 

0.  5 
0.  1 

1.  7 

0.33 
0.5*) 
1.00 

0.31 
0.53 
0.92 

0.28 
0.49 
0.86 

0.25 
0.44 

0.77 

0.23 
0.40 
0.69 

0.21 
0.36 
0.61 

0.18 
0.32 
0.55 

0.  6 
0.  8 
0  8 

0.15 
0.25 
0.43 

0.13 
0.22 
0.38 

0  11 
0.19 
0.33 

0.0!' 
0  17 
0.29 

u.os 
0.15 
0.26 

0.07 
0.13 
0.22 

•Si  "*'-"• 

18 

0.38 
0.66 
1.14 

0.38 
0.65 
1.14 

0   3 
0.6 
1.1 

0.36 
0.63 

1.10 

0.35 
0.61 
1.06 

0.33 
0.59 
1.02 

0.  2 
0.  6 
0.  8 

0.30 
0.53 
0.92 

0.28 
0.50 
0.86 

0.26 
0.46 
0.79 

0.24 
0.42 

0.72 

0.22 
0.38 
0.66 

0  20 
0  34 
0.59 

0.18 
0.31 
0.53 

0.  6 
0.  7 
0.47 

0.14 
0.25 
0.42 

0.13 
0.22 
0.38 

0.12 
0.19 
0.33 

o!l7 
0.29 

IK  if, 

0.26 

0.13 

0.23 

"£5, 

i:^ 

10 

0.59 

1  .02 

0.58 

1  .02 

0.5 

1.0 

0.57 
0.99 

0.53 

n.:,,; 

0.53 
0.93 

0.  1 

0.89 

0.48 
0.84 

0.46 
0.79 

0.43 

0.74 

0.39 
0.68 

0.36 
0.63 

0.33 
0.58 

0.30 

0.51 

'1.27 
0.46 

0.24 
0.41 

0.22 
0.37 

0.19 
0.33 

0.17 
0.30 

0.15 
0.26 

0.13 
0.23 

.*!?? 

10 

0.63 

0.53 

0.5 

0.51 

0.50 

0.48 

1:11 

0.44 

0.42 

0  40 

0  37 

0.34 

0.32 

0  29 

0.26 

0  24 

0.21 

0  19 

0  17 
0.30 

0.16 

0.27 

0.14 

0.24 

NOTE— Tbi>  table  is  bued  on  the  following  efficiencin :  100-iratt.  1.20  w.p.c.:  ISO-watt.  1.20  w.p  c.;  250-watt.  1. 15  w.u.c 


14 


Hortnontu!  dlstan 
456 


TABLE  No.  7 

of  point  Investigated  in  fi-ct  from  point  directly  teneath  Unit. 


4 

(.12 
7.04 

HI.  94 

3.46 
5.63 
8.80 

1.68 
3.15 
4.82 

O.SO 
1.30 
2.49 

0.39 
0.63 
1.37 

O.JO 
0.36 
0.64 

0.11 
0.22 
0.37 

0.07 
0.13 
0.20 

0.04 
0.08 
0.14 

0.03 
0.06 
0.09 

0.02 
0.04 
0.07 

0.02 
0.04 
0.06 

0.01 
0.03 
0.04 

u.(,l 
0.02 
0.03 

0.01 
0.02 
0.02 

0.01 
0.02 

0.02 

0.01 
0.01 
0.01 

o.'oi 

0.01 

6!6i 

0.01 

6!6i 

0.01 

o.'oi 

0.01 

5 

2.64 

2.  45 

1.45 

0.80 

0.45 

0.25 

0.15 

0.08 

0.05 

0.04 

0.03 

0.02 

0.02 

0.01 

0.01 

0.01 

0.01 

0.01 

i)  .  0  1 

o.'oi 

*.~<?** 
=Hog 

1.88 

1.76 

1.23 

0.75 

0.45 

0.28 

0.18 

0.11 

0.    7 

0.05 

0.03 

0.02 

0.02 

0.01 

0.01 

0.01 

0.01 

0.01 

0.01 

0.01 

2§i~» 

JIQ 

7 

1.35 
2.    9 
3.    7 

2.23 
3.46 

1.74 

2.76 

1.14 

1.86 

1.34 

0.92 

0.59 

0.37 

0.    5 

0.18 

0.14 

0.10 

0.07 

il  .  Ii  I) 

0.04 

t\n 

0.03 

0.02 

t'.tt 

0.02 

0.01 

K« 

a  8 

1. 
2.    3 
0.    I 

1.70 
0.80 

1.53 
0.73 

1.00 
0.55 

0.62 
0.40 

0.42 

0.32 

0.24 

0.    7 

0.12 

0.09 

0.07 

0.05 

0.04 

0.03 

0.03 

0.02 

0.02 

0.02 

0.01 

o.pi 

3%s~- 

iif 
!.o 

0.    6 
1.    2 

0.65 
1.10 

0.61 
1.04 

0.40 
0.83 

0    36 
0.59 

0.27 
0.40 

0.20 
0.30 

0.16 

0.23 

0.    1 
0.    7 

0.09 
0.14 

0.06 
0.11 

0.05 

0.08 

0.04 
0.06 

0.03 
0.05 

0.02 
0.04 

0.02 
0.03 

0.01 

0.02 

0.01 

0.02 

0.01 

0.02 

0.01 
0.02 

0.01 
0.01 

g2B£o 

£S3£3 

3°£S.a 

Slle2 

I11 

0.    3 
1.    5 

O.S1 

0.86 

0.75 

0.55 

0.38 

0.28 

0   23 

0.18 

0.14 

0.11 

0.09 

0.07 

0.06 

0.01 

0.03 

0.03 

0.02 

0.02 

0.01 
0.02 

0.01 
0.01 

?3._3r 

:??^g 

h 

0.    6 
0.    8 
1.    2 

0.45 

0.77 
1.20 

0.44 

0.74 
1.16 

0.38 
0.66 
1.01 

0.31 
0.51 
0.81 

0.24 

0.37 
0.63 

0.19 
0.27 

o.ie 

0.22 

0.11 
0.    7 

0.09 
0.14 

0.07 
0.11 

0.06 
0.09 

0.04 
0.07 

n.ii.-i 

0.06 

0.03 
0.05 

0.02 

0.04 

0.02 
0.03 

0.01 
0.03 

0.01 
0.02 

0.01 
0.02 

0.01 
0.02 

?2«     g. 

*:H! 

t,. 

0.    9 

0.39 

0.38 

JTii 

0.28 

0.23 

0.19 

0.14 

11.    1 

0.09 

0.07 

0.06 

0.05 

0.04 

0.03 

0.02 

0.02 

0.02 

0.01 

0.01 

0.01 

Ss"§3 

I.    4 

1.02 

1.00 

0.90 

«.':(•, 

0.63 

0.50 

0.41 

0.    4 

0.27 

0.22 

0.18 

0.14 

0.12 

0.10 

0.08 

0.1)7 

0.05 

0.04 

0.04 

0.03 

5[14 

0.    7 

(I.      !P 

0.57 
0.88 

0.55 
0.87 

0.52 
O.S1 

0.44 
0.69 

0.34 

0.56 

0.27 
0.48 

0.20 
0.39 

0.     6 
0.    3 

0.14 
0.27 

0    11 

0.22 

0.10 
0.19 

0.07 
0.15 

0.06 
0.12 

0.05 
0.10 

O.or, 

il.  OS 

0.04 
0.07 

0.03 
0.06 

0.02 
0.05 

0.02 
0.04 

•  0.02 
0.04 

~i-2g 
»s?fc 

3  15 

0.    9 
0.    0 

o.    ; 

0.2» 
0.4V 
0.77 

0.28 
0.48 

0.27 
0.46 

0.24 
0.40 

0.19 
0.33 

0.17 
0.26 

0   13 
0.20 

0.     1 
0.    6 

0.09 
0.13 

0.07 
0.11 

0.06 

|.i  .  i  il 

0.05 
0.08 

0.04 
0.07 

0.03 
0.06 

0.03 

0.0'. 

0.02 
0.04 

0.02 
0.03 

0.02 
0.03 

0.01 
0.02 

0.01 
0.02 

a-"!"? 

t- 

0.    6 
0.    4 
0.    8 

0.26 
0.44 
0.68 

0.2.> 
0.43 
0.67 

0.24 
0.41 

i)..;:: 

JTJi 

0.37 

ii.:.; 

0.1S 
0    30 

II       IX 

0.16 
0.25 
0.41 

0.12 
0    19 
0.35 

0.    0 
0.    6 

0.    0 

0.09 
0.13 
0.26 

0.07 
0.11 

0.22 

0.06 
0.09 
0.19 

0.05 
0.08 
0.16 

0.04 

11.117 
0.13 

0.04 
0.06 
0.11 

0.03 
0.05 
0.10 

0.02 
0.04 
0.08 

0.02 
0.04 
O.OS 

0.02 
0.03 
0.05 

0.01 
0.03 
0.05 

0.01 
0.02 

0.04 

S'O^TSJ 

IT 

0.23 
0.39 
0.60 
0.20 

0.23 
0.38 
0.60 

O.JO 

•7H 

0.38 
0.59 
0.20 

0.22 
0.37 
0.58 

O.JO 
0.34 
0.53 

0.17 
0    29 
0.45 

0.15 

u.  j:: 
0.3S 

0.12 
0.19 
0.33 

0.    0 
0.    6 
0.29 

0.09 
0.13 
0.25 

0.07 
0    11 
0.21 

0  06 
0.09 
0.18 

0.05 
O.OS 
0.16 

0.04 
0.07 
0.13 

0.04 
0.06 
0.11 

0.03 

0.05 
0.10 

0.03 
0.04 
0.09 
0.03 

0.02 
0.04 
0.07 
0.02 

0.02 
0.03 

0.06 
0.02 

0.02 
0.03 

0.05 
0.02 

0.01 
0.02 
0.04 
0.01 

!-"s; 

3=    * 
HS* 

1» 

0.19 

0.19 

O.IS 

0.18 

0.17 

0.15 

0.13 

0.11 

0.  !ll 

0.08 

0.07 

0.06 

O.OS 

0.04 

0.04 

0.03 

0.03 

0.02 

0.02 

0.02 

0.02 

Sgfij. 

III? 

90 

0.17 

0.88 

n.n 

0.  17 
0.28 
0   44 

0.16 
0.28 

0.43 

0.16 
0.27 
0.42 

ii  ir, 

0   26 
«.41 

0.14 
0    24 
0.36 

0.12 
0.21 
0.32 

0.11 
0.17 

0.28 

0.09 
0.15 
0.24 

O.OS 
0  12 
0.21 

0.07 
0.10 
0.19 

0.06 
0.09 
0.17 

0.06 
0.07 
0.13 

0.04 
0.06 
0.13 

0.04 
0.06 
0.11 

0.0.1 
O.O'i 

II.H'I 

0.03 

a.  04 

0.09 

0.02 
0.04 

O.OS 

0.02 
0.03 

0.07 

0.02 
0.03 

0.05 

0.02 
0.03 

0.05 

NOTk— This  table  i.  baled  un  the  following  cfficiencicl  :  25-watt.  1  33  W.J.C.;  40-» 


I  25  w.p.c.-  00-witt-,  1 .20  w.t 


15 


TABLE  No.   8 


Hortiontil  distinct  of  point  Invettlfited  In  feet  from  point  directly  beneath  Unit. 


4 

8.  10 

6.92 

<-.  .  1  i 

7.00 

3.72 

1.74 

0.91 

0.60 

0.27 

0.19 

0.12 

0.03 

0.08 

0.06 

ii.  'i  . 

O.H4 

0.04 

O.H3 

0.02 

0.02 

0  .  1)  1 

0.01 

1 

I.M 

10.72 

6.16 

3.65 

2.05 

!•!? 

0.65 

0.39 

t.tl 

0.16 

0.12 

0.09 

0.07 

0.06 

0.04 

0.04 

0.03 

0.06 

0.03 
0.05 

0.02 
0.04 

t.M 

0.03 

0.02 
0.03 

2S5S- 

5  oip  a 

< 

8.10 
1.97 
0.48 

7.73 
11.62 

1  .  l  :i 

3.29 

S7V5I 

1.37 

O.M1 

0.49 

0.32 

0.17 

0.13 

0.11 

0.09 

t.M 

0.05 

a.  11 

0.04 

11.  in 

0.03 

0.03 

0.02 

O.'l? 

0.02 
0.06 

trg^rw 

iLgil 

He-3 

7 
I8 

8.80 

4.65 
6.74 
1.61 

8.64 

4.45 
6.66 

11.55 

7.18 

3.78 
5.76 
10.15 

ITii 

4.31 

7.67 

1.75 
2.93 
5.21 

1.28 
2.05 
3.49 

0.93 
1.46 
2.48 

i)  .  ',  'I 
1.04 
1.80 

0.49 
0.75 
1.32 

ii.:::: 
0.56 
0.96 

0.23 
0.41 

(1  .72 

0.17 
0.31 
0.55 

0.12 
0.21 
0.43 

0.09 
0.19 
0.35 

0.07 
0.    5 
0.    7 

0.06 
0.12 
0.21 

0.05 

i>.  i.i 
0.18 

0.04 

U.MS 

0.14 

0.04 
0.07 
0.12 

0.03 
0.06 
0.10 

0.07 
0.02 
0.06 
0.08 

?|oS'i 

sir  g 

~    9 

3.60 

3.52 

3.12 

2.76 

1.61 

1.21 

0.89 

0.69 

0.51 

0.38 

t.II 

0.20 

0.14 

0.11 

0.    8 

0.06 

0.06 

0.04 

0.04 

0.03 

0.03 

£3'i?£ 

»5-E*§ 

^ 

3.  10 

4.31 

7.3V 

4.29 
7.40 

4.04 
6.98 

3.31 
5.90 

2.56 
4.59 

1.88 
3.34 

1.40 

1    tt 

1.06 
l.SO 

0.81 
1.40 

0.62 
1.08 

0.48 

(1.85 

0.38 
0.66 

0.30 

t.a 

0.24 
0.41 

0.    9 
0.    3 

0.15 
0.27 

0.13 
0.23 

0.10 
0.19 

0.04 
0.09 
0.16 

0.03 
0.07 
0.13 

0.03 
0.06 
0.11 

Ss"33' 
°§B»2 

fll 

2.41 
3.56 

2.37 
3.56 

2.26 

1.90 

1.41 

1.03 

0.81 

0.64 

0.52 

0.42 

0.34 

0.26 

0.19 

0.15 

0.    2 

0.09 

0.07 

ii.  us 

0.05 

0.04 

0.03 
0.0.8 

?.|l! 

f  12 

2.03 
2.99 

2.00 
2.99 

1.93 
2.90 

1.68 
2.56 

1.30 
2.13 

0.97 
1.69 

0.77 
1.30 

0.64 
1.03 

0.50 
0.81 

0.41 
0.66 

0.33 
0.52 

0.26 
0.41 

0.22 
0.33 

0.16 
0.27 

0.    3 
0.    2 

0.10 
0.18 

0.08 
0.15 

0.07 
0.13 

0.06 
0.11 

0.05 
0.09 

0.04 
0.08 

§"31  a 

!8»28 

I  ls 

1.72 
2.56 

1.71 
2.55 

1.66 
2.48 

1.60 
2.26 

1.22 
1.93 

0.64 

0.52 

0.35 

!ilss 

Kit 

1.49 

1.48 

1.44 

1.34 

1.11 

II  .  S  ,' 

0.70 

0.56 

0.47 

rii 

0.32 

STii 

0.23 

0.19 

0  .  1  « 

0.13 

0.10 

0.08 

0.06 

0.06 

0.05 

•"•3  Ol3 

3-is^  = 

in 

1.30 
1.92 
3.27 

1.29 
1.92 
3.31 

1.26 
1.89 

3.28 

1.21 
1.79 
3.10 

1.04 
1.59 

0.80 
1.37 

0.67 
1.13 

0.54 

0.92 

0.46 

0.75 

0.39 
0.62 

0.32 

0.52 

0.28 
0.43 

0.23 
0.36 

>.:•» 
0.30 

0.17 
0.25 

0.14 
0.21 

0.11 
0.18 

0.09 
0.15 

0.07 
0.13 

0.06 
0.11 

0.06 
0.10 

isi:s 

Is  9* 

£l« 

1.14 
1.68 

1.13 
1.68 

1.11 
1.66 

1.06 
1.60 

0.95 
1.44 

0.75 
1.26 

0.63 
1.08 

0.61 

O.S9 

0.43 

0.73 

0.37 
0.61 

0.32 

0.51 

0.27 
0.43 

0.23 
0.36 

0.20 
0.31 

0.17 
0.26 

0.14 

o  .  i  :• 

0.12 
l.ll 

0.10 
0.16 

0.08 
0.14 

0.07 
0.12 

0.06 
0.10 
0.18 

P&l 

1.01 

1.00 

0.99 

0.96 

0.87 

0.71 

0.59 

0.49 

0.42 

0.36 

0.31 

0.26 

0.23 

0.19 

0.17 

0.16 

0.13 

0.11 

0.09 

0.07 

0.06 

Ii"  *- 

11 

0.~!<l 

1.33 

2.27 

(:.'.'-a 
1.33 
2.28 

0.88 
1.32 
2.29 

0.86 
1.29 
2.23 

0.78 
1.20 
2.10 

0.67 
1.07 
1.90 

0.56 
0.95 
1.69 

0.47 
0.82 
1.47 

0.40 
0.69 
1.24 

0.34 
0.58 
1.03 

0.30 
0.49 
0.87 

0.26 
0.42 

".;.! 

0.23 
0.36 
O.S2 

0.19 
0.31 
0.53 

0.17 
0.27 
0.46 

0.16 
0.23 
0.39 

0.13 
0.20 

0.11.1 

0.12 
0.17 
0.30 

0.10 
0.15 

U.Lfi 

0.08 
0.13 
0.23 

0.07 
0.11 
0.20 

•~s*; 
ITic 

19 

0.81 
1.19 
2.04 

0.81 
1.19 
2.05 

0.80 
1.19 
2.06 

0.78 
1.16 
2.01 

0.74 
1.10 
1.92 

0.64 
1.00 
1.76 

0.63 

0.89 

1.58 

0.45 
0.78 
1.39 

0.39 
0.67 
1.19 

0.33 
0.66 
1.01 

0.29 
0.48 
9.15 

0.26 
0.41 
0.72 

0.23 

'1  .   •>:  ': 

0.61 

0.19 
0.30 
0.53 

0.17 
0.27 
0.46 

0.15 
0.23 
0.40 

0.13 
0.20 
0.35 

0.11 
0.18 
0.31 

0.10 
0.15 
0.27 

0.09 
0.13 
0.23 

0.07 
0.11 
0.20 

aS&g 

»  O.  i    i 

20 

m 

1.08 

1  1 

0.73 
1.08 
1.8$ 

0.72 
1.07 
1.85 

0.70 
1.06 

1.83 

0.68 
1.01 

1.75 

0.61 
0.92 
1.62 

0.51 
0.83 
1.47 

0.43 
0.74 
1.31 

0.38 
0.64 

1.15 

0.33 

0.55 

>!.'.<'.< 

0.28 
0.47 
0.83 

0.25 
0.40 
0.71 

0.22 
0.35 

0.61 

Vl9 
0.30 

O.f>2 

0.17 
0.20 
0.45 

0.15 
0.23 
0.40 

0.13 
0.20 
0.35 

0.11 
0.18 
0.31 

0.10 
I.M 

0.27 

0.09 
0.14 
0.24 

0.08 
0.12 
0.21 

Hans— This  Ublc  i.  bucd  an  tic  following  cfficicaeies  :  100-watt,  1.20  w.p.c.;  ISO-watt,  1.20  w.p.c.;  2oO-watt,  1.16  w.p.c 


16 


TABLE  No.  9 

Eeflection  Co-efficients  of  Walls  and.  Ceilings.        r    ff  '     t    f     i 
Kind  Color  Eeflection-K      i-K 

Plain  ceiling  Faint  green 53  2.13 

Light  yellow 49  1.96 

Faint   pink 43  1.75 

Pale  bluish  white 31  1.45 

Light  gray  green 23  1.30 

Crepe  Medium  green 19  1.23 

Medium  red 08  1.09 

Deep  green   06  1.06 

Cartridge  Medium  light  buff 44  1.79 

Light  blue 20  1.25 

Pale   pink    19  1.23 

Light  green 18  1.22 

Striped  Deep  cream  silvery 57  2.32 

("Two-toned")      Light  strawberry  pink 43  1.75 

Light  green 26  1.35 

Medium  red 08  1.09 

Miscellaneous         Light  gray 38  1.61 

Light  green  and  gold 28  1.39 

(minute  figuring,  much  gold) 

17 


TABLE  No.  10 

Average  Percentage  of  Eeflection  from  Walls  and  Ceilings. 

Increase 
Ceiling  Walls  over  calculated 

Very  dark   Very  dark   0% 

Medium Very  dark   15% 

Medium Medium 40% 

Very  light Very  dark    30% 

Very  light Medium 55% 

Very  light Very  light 80% 


TABLE  No.  11 — Spacing  of  Units  for  Uniform  Illumination 

Clear  Holophane  .  Height  above 

Reflectors,  Type  Plane  to  be  lighted 

Extensive 1/2  D 

Intensive 4/5  D 

Focusing 4/3  D 

D  =  Distance  between  units  =  Side  of  square,  when  units  are  placed  in  squares  =  Average 
side  of  rectangle,  when  units  are  placed  in  rectangles. 


18 


TABLE  No.  12 
Current  Taken  by  Incandescent  Lamps 


Tanta- 
Mazda                                          lum 

Gem 

Carbon 

1    Watts  per  lamp     

25 

19.1 
.23 

26 
495 

40 

32.5 
.36 

17 
550 

60 

50.8 
.55 

11 

560 

100 

84.7 
.91 

6 

510 

150 

127.0 
1.36 

4 
510 

250 

222.0 
2.27 

2 
445 

400 

354.0 
3.64 

1 
355 

500 

442.0 
4.55 

1 

440 

40 

20 
.36 

16 

320 

80 

40 
.73 

8 
320 

50 

20.0 
.46 

13 
260 

100 

40.7 
.91 

6 
245 

50 

16.8 
.46 

13 

220 

100 

33.6 
.91 

6 

200 

2.  Candle-power  at  rated  ef- 
ficiency   

3.  Amperes  per  lamp  at  110  volts 
4.  Permissible  number  of  lamps 
per    cut-out  

5.  Candle-power  per  cut-out  

19 


TABLE  No.  13 


Carrying  Capacity  of  Wire  as  Established  b/  the  National  Board  of  Fire  Underwriters 


B  &  S 
Gauge 

18 
16 
14 
12 
10 

8  . 

6 

5 

4 

3 

2    . 

1 

0 

00 

000 

0000 


Circular 
Mils 

1,624 

2,583 

4,107 

6,530 

10,380 

16,510 

26,250 

'  33,100 

41,740 

52,630 

66,370 

83,690 

105,500 

133,100 

167,800 

211,600 


Eubber  Covered 

Wire. 
Amperes 

3 
6 

12 

17 

24 

33 

46 

54 

65 

76 

90 
107 
127 
150 
177 
210 


Weather  Proof 

Wire. 
Amperes 

5 

8 

16 

23 

32 

46 

65 

77 

92 
110 
131 
156 
185 
220 
262 
312 


The  question  of  drop  is  not  considered  in  the  above  table. 

No  wire  smaller  than  No.  14  is  used  except  for  fixture  work  and  flexible  cord. 

20 


TABLE  No.  14 

Table  Showing  Size  of  Wire  for  Drop  of  One  Volt 


Silt 

Distance  in  Feel  (o  Center  ol  Distribution 

Nwiri'      20'        25'        30'        35' 
B.iS. 

40'         45'        60'         60'         70'        80'        90       100'     120'     140'     160'     180'     200' 

14      9.5         7.60       6.34       5.42 
12    15.1       12.08     10.06       8.64 
10    24.0       19.20     16.00     13.60 
8    ~~33     |30.55     25.45     21.80 

4.75       4.22       3.80       3.17       2.62       2.37       2.11      1.90      1  58       1  35      1.18      1.06       1.95 
7.55       6.61       6.04       5.03       4.31       3.78       3.36      3  02      2.51       2.15      1.88      1.68      1.51 
12.00     10.66       9.60       8.00       6.86       6.00       5.33      4.80      4.00       3.43      3.00      2.66      2.40 
19.10     16.90     15.28     12.72     10.90       9.55       8.49      7.64      6.36       5.45      4.77      4.24      3.82 
30.30     26.95     24.25     20.20     17.30.   15.15     13.48    12.12    10.10       8.66      7.58      624      6.06 
38.25     34.00     30.60     25.50     21.85     19.12     17.00    15.30    12.75     10.92      9.56      8.50      7.65 
48.25     42.90     38.60     32.17     27.58     24.13     21.44    19.30    16.08     13.79    12.06    10.72      9.65 
60.9       54.1       48.7       40.60     34.80     30.45     27.05    24.35    20.30     17.40    15.22    13.52    12.17 
76.6       68.1.      61.4       51.1       43.8       38.30     34.05    30.66    25.55     21.90    19.15    17.02    15.33 
95.5       84.9       76.4       69.5       54.6       47.75     42.45    3820    31.85     27.30    23.86    21.22    19.10 
122.0     108.4       97.6       81.3       69.7       61.00     54.20    48.80    40.65     34  85    30.50    27.10    24.40 

6       46          46       40.4       34.60 
5        54          54       51.0      43.75 
4        65          65       64.5       55.15 

3       76          76          76       69.6 
2       00          90          90       87.6 

1      107         107         107    '     107 
0      127         127         127         127 
00      150         150        150         150 
000      177         177         177         177 
0000      210        210        210        210 

150       136.6     123.0     102.5       87.9       76.80     68.30    61.50    51.25     43.90    38.40    34  15    30.75 
177       172.2     155.0     129  2     110.7       96.9       86.1      77.5      64.6       55.35    48.45    43.05    38.75 

210         210    ~|l9o.6      1C3  0     139.6     122.3     109.6      97.8      81.5       69.8      61.15    5430    48.90 

r  1-  ....j  A  —  I  D  21.02 

Currents  found  under  the  broken  line  are  the  maximum  allowable  b;  National  Board  of  Underwriters  for  the  sire  specified  (Rubber  Covered  Wire)    The  drop  for 

lighting  and  power  load  multiply  the  values  given  in  the  table  by  .82.    If  A.  C.  two  phase  (4  wire)  or  three  phase  (3  wire),  lor  lighting  load  multiply  values  given  in 

21 


TABLE  No.  15 

Showing  Total  Cost  of  Producing  Light  with  "MAZDA"  Lamps  at  High,  Medium  and  Low  Efficiency 


Nominal  Watts          

25 

40 

60 

100 

Efficiency  Step 

High 

Mod. 

Low 

High 

Mt-d. 

Low 

High 

Med. 

Low 

High 

Med. 

Low 

Watts  per  Candle 

1.31 
25  0 
19  1 

187 
7.48 
1000 

$0.65 

.65 

1.37 
24.2 
17  7 

173 
7.16 
1300 

to  65 
.50 

1.43 
23.4 
16.4 

160 
6.86 
1700 

$065 
38 

1.23 
40.0 
32.6 

319 
7.97 
1000 

$070 

70 

1.28 
38.9 
30  4 

298 
767 
1300 

$0  70 
54 

1  33 

37.8 
28.5 

'277 
7.37 
1TOO 

$0  70 
41 

1  18 
60.0 
50.8 

498 
8.30 
1000 

$1  00 
1  00 

1.23 
58.2 
47.3 

464 
7  97 
1300 

$1.00 

77 

1.28 

56.5 
44.2 

433 
7.67 
1700 

$1.00 
59 

1.18 
100.0 
84.7 

830 
8.30 
1000 

$1.35 
1.35 

1.23 
97.0 
78  9 

773 
7.97 
1300 

$1.35 
1.04 

1.28 
94.2 
73.6 

722 
7.67 
1700 

$1.35 
.79 

Actual  Watts 

Candle-Power 

List  Price—  Clear  . 

Variable  Cost  of 
Power 

*Combined  Cost  of  Power  and  Lamp  Renewals  per  100,000  Lumen-Hours  in  Dollars 

1C  per  Kw-hr 

$0  48 
62 

75 

.88 
1.02 
1.15 

1  42 
1  89 
1  96 

$0.43 
57 
71 

85 
99 
1  13 

1  41 
1  69 

1  97 

SO  38 
53 
68 

82 
.97 
1  11 

1  41 

1  70 
1  99 

$0.34 
47 
59 

72 
84 
97 

1  22 
1  47 
1  72 

$0.31 
44 
.57 

71 
84 
97 

1.23 
1.49 
1.75 

$0.28 
.42 
.56 

69 
83 

96 

1  24 

1  51 
1  78 

$0.33 
.45 
57 

69 
81 
93 

1  17 
1  41 
1  66 

$0  29 
42 
.54 

67 
79 
92 

1  17 

1  42 
1.67 

$0.27 
40 
.63 

66 
79 
.92 

1  18 
1  44 
1  70 

$0.28 
.40 
52 

64 
76 
.88 

1.12 
1  36 
1  60 

$0  26 
.39 
51 

64 
76 
.89 

1.14 
1.40 
1.65 

$0.24 
.J7 
.60 

.63 
.78 
90 

1.1$ 
1.42 

1.68 

2c   "       "    " 

3c    

4c   '  

6c   "       "    "   

6c   

gc   

10c   

12c    

*For  each  one  cent  difference     ( 
in  cost  of  lamp  add  or  subtract  \ 

0.0054 

0045 

0037 

0031 

.0026 

0021 

.0020 

.0017 

0014 

.0012 

0010 

.0008 

100.000  Lumen-Hours  from  a  "Mazda"  Lamp  is  equal  to  10,200  Mean  Horizontal  Candle-Hours. 

22 


TABLE  No.  15 — Continued. 


Nominal  Watts 

150 

250 

400 

500 

Efficiency  Stop..  . 

High 

Med. 

Low 

High 

Med. 

Low 

High 

Mcd. 

Low 

HiKh 

Mcd. 

Low 

Watts  per  Candle  
Actual  Watts 

1.18 
150.0 
127.0 

1245 
8.30 
1000 

$2.00 
2.00 

1.23 
145.5 
118.3 

1160 
7.97 
1300 

$2.00 
1.54 

1.28 
141.2 
110.4 

1083 

7.67 
1700 

$2.00 
1.18 

1.13 
250.0 
222.0 

2168 
8.67 
1000 

$2.75 
2.75 

1.18 
242.0 
204.2 

2009 
8.30 
1300 

$2  75 
2.12 

1.23 
235.0 
191.0 

1873 
7.97 
1700 

$2.75 
1.62 

1.13 
400.0 
354.0 

3470 
8.67 
1000 

$5.00 

5.00 

1.18 
387.0 
328.0 

3215 
8.30 

1300 

$5.00 
3.85 

1.23 
376.0 
306.0 

3000 
7.97 
1700 

$5.00 
2.94 

1.13 
500.0 
442.0 

4335 
8.67 
1000 

$5.50 
5.50 

1.18 
484.0 
410.0 

4020 
8.30 
1300 

$5.50 

4.23 

1.23 
470.0 
382.0 

3745 
7.97 
1700 

$5.50 
3.24 

Candle-Power    

Hours  Lite- 

List  Price  —  Clear  

Variable  Cost  of 
Power 

*Combined  Cost  of  Power  and  Lamp  Renewals  per  100,000  Lumen-Hours  in  Dollars 

Ic  per  kw-hr. 

$0  28 
.40 
.52 

.64 

.77 
.89 

1.13 
1.37 
1.61 

50.  2S 
.38 
.51 

.63 
.76 
.88 

1.13 
1.38 
1.63 

$0.24 
.37 
.50 

.63 
.76 
.89 

1.15 
1.41 
1.67 

$0.24 
.36 
.47 

.59 
.70 
.82 

1.05 
1.28 
1.51 

$0.23 
.35 
.47 

.59 
.71 
.83 

1.07 
1.31 
1.55 

$0.21 
.34 
.47 

.59 
72 

.84 

1.10 
1.35 
1.60 

$0.26 
.37 
.49 

.60 
.72 
.83 

1.06 
1.29 

1.52 

$0.24 
.36 
.48 

.60 
.72 
.84 

1.08 
1.32 
1.56 

$0.22 
.35 
.47 

.59 
.72 

.85 

1.10 
1.35 
1.60 

$0.24 
.36 
.47 

.59 
.70 
.82 

1.05 
1.28 
1  51 

$0.23 
.35 
.47 

.59 
.71 
.83 

1.07 
1.31 
1.55 

$0.21 
.34 
.46 

.59 
.71 
.84 

1.09 
1.34 
1.59 

2c    

3c    

4c    .             

Sc    

8c    '  

10c    

12c    . 

in  cost  of  lamp  add  or  subtract  $ 

0.0008 

.0007 

.0005 

.0005 

0004 

.0003 

.0003 

.0002 

.0002 

0002 

.0002 

0002 

100.000  Lumen-Hours  from  a  "Mazda"  Lamp  is  equal  to  10,200  Mran   Horizontal  Candle-Hour 


23 


TABLE  No.  16 

Showing  Total  Cost  of  Producing  Light  with  Tantalum  Lamps  at  High,  Medium  and  Low  Efficiency 


Nominal  Watts 

25 

40 

50 

80 

HiBh 

Med. 

Low 

High 

Med. 

Low 

High 

Med. 

Low 

High 

Med. 

Low 

Watts  por  Candle  

1.9Y 

2  05 

2  14 

1  79 

1.87 

1.95 

1.79 

1.87 

1.95 

1.79 

1.87 

1.95 

Actual  Walls..  .. 

25.0 
12.7 

'  126 
5.04 
1000 

$0.50 
.60 

24.2 

11.8 

117 
4.83 
1300 

$0.50 
.38 

23.5 

11.0 

109 
4.64 
1700 

$0.50 
.29 

40.0 
22.3 

221 
5.54 
800 

$0.50 
.63 

88.8 
20  7 

206 
6.31 
1100 

$0.50 
.45 

37.6 
19.3 

191 
6.09 
1600 

$0.50 
.33 

50.0 
27.9 

277 
6.54 

800 

$0.50 
.63 

48.5 
25.9 

257. 
5.31 
1100 

$0.50 
.45 

47.0 
24.1 

239 
6.09 

15CO 

$0.50 
.C3 

80.0 
44.6 

443 
5.54 
6CO 

$0.85 
1.42 

77.6 
41.5 

412 
5.31 
800 

$0.85 
1.06 

T5.2 
38.6 

383 
5.09 
1050 

$0.85 
.81 

Lumens  per  Watt  . 

Hours  Life  (D.  C.)  

Renewals  per  1000  hr 

Variable  Cost  of 
Power 

*Combined  Cost  of  Power  and  Lamp  Renewals  per  100,000  Lumen-Hours  in  Dollars. 

$0.60 
.79 
.99 

1.19 
1  39 
1.69 

1.88 
2.38 
2.79 

$0.54 
.74 
.95 

1.16 
1.36 
1.57 

1.98 
2.39 
2.81 

$0.49 
.71 
.92 

1  13 
1.36 

1.66 

1.99 
2.43 

2.86 

$0.46 
.64 
.83 

1.01 
1.19 
1.37 

1.73 
2.09 

2  45 

$0.41 
.60 
.79 

.97 
1.16 
1.35 

1.73 
2.10 

2.49 

$0.37 
.57 
.77 

.98 
1.16 
1.36 

1.75 
2.14 
2.54 

$0.41 
.59 
.77 

95 
1.13 
1.31 

1.67 
2.03 
2.39 

$0.37 
.55 
.74 

.93 
1.12 

1.31 

1.69 
2.06 
2.44 

SO.  34 
.53 
.73 

.93 
1.12 
1.32 

1.71 
2.11 
2.50 

$0.50 
.68 
.86 

1.04 
1.22 
1.40 

1.76 
2.12 
2.49 

$0.45 
.63 
.82 

1.01 
1.20 
1.39 

1.77 
2.14 
2.52 

$0.41 
.60 
.80 

1.00 
1.19 
1.39 

1.78 
2:i8 
2.57 

2c  "     "    " 

3c   "     ''    "• 

4c   

Sc   

6c    

8c    "      "    '' 

lOc    

12c    

'For  each  one  cent  difference    1 
in  cost  ol  lamp  add  or  subtract  i 

0.0079 

.0066 

.0054 

.0057 

.0044 

.0035 

.0045 

.0035 

.0028 

.0038 

.0030 

.0025 

100.000  Lumen-Hours  from  a  Tantalum  Lamp  is  equal  to  10.100  Mi-an  Horizontal  Candle-Hours. 


24 


TABLE  No.  17 

Showing  Total  Cost  of  Producing  Light  with  Gem  Lamps  at  High,  Medium  and  Low  Efficiency 


Nominal  Watts        

40 

50 

60 

80 

100 

Efficiency  Step  

High 

Med. 

Low 

Hifth 

Med. 

Low 

High 

Med. 

Low 

HiKh 

Med. 

Low 

HiKh 

Mod. 

Low 

Watts  per  Candle 

2.66 
40.0 
15.6 

162 
4.05 
600 

10.21 
35 

2.71 
38.7 
14.2 

148 
3.82 
900 

$0.21 
23 

2.89 
37.3 
12.9 

135 
3.59 
1300 

$0.21 
16 

2.60 
50.0 
20.0 

207 
4.15 
700 

$0.21 
30 

2.65 
48.4 
18.3 

189 
3.91 
1000 

$0.21 
21 

2  81 
467 
166 

172 
3.66 
1500 

$0.21 
.14 

2.50 
60.0 
24.0 

249 
4  15 
700 

$0.21 
.30 

2  66 
08.0 
21  9 

227 
3  91 
1000 

$0.21 
21 

2.81 
56.0 
19.9 

206 

3  68 
1500 

$0.21 
14 

2  46 
80.0 
32.5 

337 
4.21 

700 

$0.35 
50 

2.60 
77  4 
29.8 

308 
3.98 
1000 

$0.35 
35 

2.78 
74.6 
26.8 

278 
3.73 
1500 

$0  35 
23 

2  46 
100.0 
40.7 

419 
4.19 
660 

$0.35 

54 

2.60 
96.7 
37,2 

384 
3.96 
950 

$0.35 
.37 

2.78 
93.2 
33.5 

346 

3.71 
1400 

$0.35 
.25 

Actual  Watts                 .    . 

Candle-Power     

Hours  Life 

List  Price  —  Clear. 

Renewals  per  1000  hr  

Variable  Cost  of 
Power 

'Combined  Cost  of  Power  and  Renewals  per  100,000  Lumen-Hours  in  Dollars 

Ic  per  kw-hr.    . 

$0-46 
-71 
96 

1.20 
1.46 

1.70 

2.  It 
269 
3.18 

$0-42 
.68 
.95 

1  21 
1.47 
1.72 

2  24 
2  78 
3.30 

$0  40 
87 

.95 

1.23 
1.50 
1.78 

2  33 
2.88 
3.43 

$0.39 
.63 
-87 

1  12 
1.38 

1  60 

2.08 
2  58 
308 

$0.37 
62 

-88 

1.14 
1.39 
1.65 

2.16 
2.87 
3  18 

SO.  36 
.62 
-90 

1.17 
1.44 
1.71 

£.25 

2  80 
3.34 

$0.36 
60 
-85 

1.09 
1.33 
1.57 

2.05 
2.63 
3.01 

$0-35 
60 
.86 

1  12 
1.37 
1.63 

2  14 
2.65 
3.16 

$0-34 
.61 

•88 

1  15 
1-43 
1-70 

2.25 
2.79 
3  34 

$0  39 
62 
86 

1-16 
1  34 
1.67 

2.05 
2  62 
3-00 

$0.36 
62 

87 

1.12 
1.37 
1.62 

2.12 
2.63 
3-13 

SO  36 
62 

89 

1.16 
1.42 
1  69 

2.23 
2.77 
3-30 

$0-37 
-61 
.84 

1  08 
1  32 
1-68 

2-03 
2-61 

2  99 

$0-35 
.60 

85 

1.10 
1.36 
1-61 

2-11 
2  62 
3-12 

SO.  34 

.61 
88 

1.15 
1.42 
1-69 

2.23 
2  77 
3.31 

2c    

3c    

4c    

5c    ... 

6c    

8c    

lOc    "      '    " 

12c    "    "    " 

•For  each  one  cent  differ-     | 
ence  in  price  of  lamp  add    • 
or  subtract  ) 

0.0103 

.0075 

0057 

0069 

0053 

0039 

0067 

0044 

.0032 

.0042 

.0032 

0024 

0037 

.0027 

0021 

100.000  Lumen-Hours  from  a  Gem  Lamp  is  equal  to  9  650  Mean  Horijontal  Candle-Hour 


25 


TPABLE  No.  18 

Showing  Total  Cost  of  Producing  Light  with  Carbon  Lamps  at  High,  Medium  and  Low  Efficiency 


Nominal  Watts  

25 

30 

50 

60 

iOO 

120 

Efficiency  Stop  

High 

Mi-d. 

Low 

High 

Med. 

Low 

Hitth 

Mod. 

Low 

High 

Mod. 

Low 

HiBh 

Med. 

Low 

High)    Med. 

Low 

Watts  per  Candle  .  . 
Actual  Watts  

3.10 
25.0 

8.1 

S3.  6 
3  34 

500 

$0.20 
.40 

3.31 
24  1 
7.3 

75.4 
3.15 
725 

JO.  20 

.28 

3.52 
23.2 

6.6 

68.  1 
2  94 
1050 

$0  20 

3.23 
!0.0 
9.3 

96.4 
3.21 
1050 

50  20 
.19 

3.46 
28.9 
8.4 

87.0 
3.00 
1500 

$0  20 
13 

3.69 

27.8 
7  5 

77  7 
2.81 
2100 

$020 
'10 

2  97 
50  0 
16  8 

174 

3  49 
700 

$0  20 
29 

3.18 
48.2 
15  2 

158 
3.26 
100Q 

$0.20 
.20 

3.39 
46  4 
13.7 

142 
3  C« 
1500 

$0.20 
IS 

2.97 
60  0 
20.2 

208 
3  49 
700 

$0  20 
29 

3  18 
67  8 
18  3 

190 
3  26 

1000 

$0  20 

20 

3  39 
55.7 
16.4 

170 
3  06 
1500 

$0  20 
13 

2  97 
100.0 
33.6 

349 
3  49 
600 

SO  30 
.50 

3.18 
96.4 
30.5 

316 
3  26 
850 

$0.30 
35 

3  39 
92.9 
27  4 

284 
3  06 
1350 

$0  30 
.22 

2.97 
120.0 
40.4 

419 
3.49 
600 

$0  30 
50 

3  18 
115.8 
36.6 

379 
3.26 

850 

$0.30 
.35 

3.39 
111.4 
32.8 

340 
3.06 
1350 

$0.30 
.22 

Candle-Power  
Total  Lumens 

Lumens  per  Watt-. 
Hours  Life  

List  Price-Oar.... 
Renewals  per  1000  hr. 

Variable  Cost  of 
Power 

*Combined  Cost  of  Power  and  Lamp  Renewals  per  100,000  Lumen-Hours  in  Dollars 

lc  per  kvvlir   

$0.78 
1.08 
1.38 

1  68 
1  97 
2.27 

2  87 
3  47 

$0.69 
1  01 
1  33 

1.64 

1  96 
2.28 

2  92 
3.56 

$0  62 
96 
1  30 

1  63 

1  97 
2.31 

2  99 
3.67 

SO  51 
82 
1  13 

1  44 

1  75 
2  07 

2  69 
3.31 

$0.49 
.82 
1  15 

1  48 
1  81 
2  15 

2.81 
3.48 

$048 

B4 
1.20 

1  55 
1  91 
2.27 

2  99 
3  70 

50  45 
74 
1.03 

1.31 
1.60 
1  89 

2  46 
3.04 

$0.43 
74 
1  04 

1.35 
1.65 
1  96 

2.57 
3.18 

»  42 

.75 
1.07 

1  40 
1.73 
2.05 

2  71 
3.36 

$0.43 
.71 
1  00 

1  29 

1  58 
1.87 

2.44 
3.02 

SO  41 

71 
1  02 

1.32 
1  63 
1.93 

2  54 
3.15 

$0  41 

.73 
1.06 

1  39 
1.72 
2.04 

2  70 
3.38 

SO  43 
72 
1.00 

1  29 
1.58 
1  86 

2  44 

3.01 

$042 
72 

1.03 

1.33 
1.64 
1  94 

2.55 
3.16 

$0.41 

.73 
1.06 

1.39 
1.71 
2.04 

2.70 
3.35 

$0.41 
69 
98 

1  27 

1  65 
1.84 

2.41 

2  98 

$0.40 
70 
1.01 

1.32 
1  62 
1  93 

2.54 
3.15 

$0.39 
72 
1.05 

1.38 
1.70 
2.03 

2.69 
3.34 

2c    '     
3c    

4c    

5c    

6c    "    "    " 

gc    

10c    

•For  each  one  cent    ) 

lamp  add  or  subtract  > 

0.0239 

.0183 

.0140 

.0079 

.0077 

.0061 

.0082 

0063 

.0047 

0069 

.0053 

.0039 

.0048 

.0037 

.0026 

0040 

.0031 

.OC22 

100.000   Lumen-Hours  (rom  a  Carbon   Lamp  is  equal  to  9,650  Mean  Horizontal  Candle-Hours. 


26 


TABLE  No.  19 

Intrinsic  Brilliancy  of  Light  Sources  Candle-power 

per  sq.  in. 

Moore  tube    0.3  —      1.75 

Frosted  incandescent   2.0  —       5 

Candle   3.0  —       4 

Gas   flame    3.0  —       8 

Oil    lamp 3.0  —       8 

Cooper   Hewitt    lamp 17 

"Welsbach  gas  mantle 20.0  — •     50 

Acetylene 75.0  —  100 

Enclosed  A.C.  arc 75.0  —  200 

Enclosed    D.C.    arc 100.0  —  500 

Incandescent  Lamps — 

Carbon  3.5  watts  per  candle 375 

Carbon  3.1  watts  per  candle 480 

Metallized  carbon  2.5  watts  per  candle 625 

Tantalum   2.0   watts   per  candle 750 

"MAZDA"  1.25  watts  per  candle 875 

' '  MAZDA  ' '  1.15  watts  per  candle 1000 

Nernst    1 :5   watts  per   candle 2200 

Sun    on    horizon 2000 

Flaming  arc    5000 

Open  arc  lamp 10,000-50,000 

Open    arc    crater 200,000 

Sun    30°    above    horizon 500,000 

Sun    at    zenith 60o!oOO 

27 


TABLE  No.  20 


"MAZDA" 

3 

9 

2 

a 

£ 

°$ 
l> 

03 

m 

03  "-; 

E-l 

O 

Watts  per  Lamp  

25 

40 

60 

100 

150 

250 

Effective  Lumens  ner  Lamn  

95 

160 

250 

420 

630 

1090 

Lumens 

per  Watt  

3.8 

4.0 

4.2 

4.2 

4.2 

4.3 

2.5 

1.8 

1.5 

28 


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